feat: add device position undo history

Issue: #74
User-Visible: yes

src/device-position-history.ts

@@ -0,0 +1,68 @@
+export interface DevicePlacement {
+  x: number;
+  y: number;
+  s?: string;
+}
+
+export interface DeviceLayoutEntry extends Record<string, unknown> {
+  x: number;
+  y: number;
+  s?: string;
+  k?: number;
+}
+
+export type DeviceLayout = Record<string, DeviceLayoutEntry>;
+
+export interface DevicePositionState {
+  deviceId: string;
+  spaceId: string;
+  placement: DevicePlacement | null;
+}
+
+export function devicePlacement(layout: DeviceLayout, deviceId: string): DevicePlacement | null {
+  const entry = layout[deviceId];
+  if (!entry || !Number.isFinite(entry.x) || !Number.isFinite(entry.y)) return null;
+  return {
+    x: entry.x,
+    y: entry.y,
+    ...(typeof entry.s === 'string' ? { s: entry.s } : {}),
+  };
+}
+
+export function sameDevicePlacement(
+  left: DevicePlacement | null,
+  right: DevicePlacement | null,
+): boolean {
+  if (left === null || right === null) return left === right;
+  return left.x === right.x && left.y === right.y && left.s === right.s;
+}
+
+/**
+ * Apply only placement fields. Existing/future sibling fields deliberately
+ * survive an update; a null placement removes the complete persisted position
+ * record because the layout schema does not permit a record without x/y.
+ */
+export function applyDevicePlacement(
+  layout: DeviceLayout,
+  deviceId: string,
+  placement: DevicePlacement | null,
+): DeviceLayout {
+  if (placement === null) {
+    if (!(deviceId in layout)) return layout;
+    const next = { ...layout };
+    delete next[deviceId];
+    return next;
+  }
+
+  const current = { ...(layout[deviceId] || {}) } as Record<string, unknown>;
+  delete current.x;
+  delete current.y;
+  delete current.s;
+  const entry: DeviceLayoutEntry = {
+    ...current,
+    x: placement.x,
+    y: placement.y,
+    ...(placement.s !== undefined ? { s: placement.s } : {}),
+  };
+  return { ...layout, [deviceId]: entry };
+}

src/houseplan-card.ts

@@ -241,6 +241,14 @@ import { hasTranslation, langOf, t, type I18nKey } from './i18n';
 import { LANGUAGE_RUNTIME, subscribeLanguageLoadFailures } from './i18n/registry';
 import { languageLoadingTemplate, languageRenderGate } from './i18n/language-runtime';
 import { CommandStack } from './command-stack';
+import {
+  applyDevicePlacement,
+  devicePlacement,
+  sameDevicePlacement,
+  type DeviceLayout,
+  type DevicePlacement,
+  type DevicePositionState,
+} from './device-position-history';
 import { resolvedSvgScreenBlend, svgScreenBlendSupported } from './glow-blend';
 import {
   buildGlowClipGeometry, buildLightBarrierScene, createGlowRuntimeState,
@@ -789,6 +797,21 @@ interface DeviceInboxDialogState {
 
 type FixedFloorState = FixedFloorSelection | { kind: 'pending'; value: unknown };
 
+interface DeviceDragState {
+  id: string;
+  spaceId: string;
+  displayName: string;
+  pointerId: number;
+  source: Element | null;
+  sx: number;
+  sy: number;
+  ox: number;
+  oy: number;
+  moved: boolean;
+  before: DevicePlacement | null;
+  start: DevicePlacement;
+}
+
 export class HouseplanCard extends LitElement {
   public _editorRuntime: import('./houseplan-editor-runtime').HouseplanEditorRuntime | null = null;
   public _onboardingRuntime: import('./houseplan-onboarding-runtime').HouseplanOnboardingRuntime | null = null;
@@ -925,7 +948,7 @@ export class HouseplanCard extends LitElement {
   private _config?: CardConfig;
 
   private _space = 'f1';
-  private _layout: Record<string, { x: number; y: number; s?: string; k?: number }> = {};
+  private _layout: DeviceLayout = {};
   private _serverStorage = false;
   private _loadOk = false;
   /** null until config/get answers; then mirrors auth.may_write for this user. */
@@ -1702,6 +1725,9 @@ export class HouseplanCard extends LitElement {
   private _tool: MarkupTool = 'draw';
   /** UX-04: one named, 50-step command history for every plan-geometry tool. */
   private _geometryHistory = new CommandStack<SpaceGeometryState>(50);
+  /** #74: independent session-local history for manual device placements. */
+  private _devicePositionHistory = new CommandStack<DevicePositionState>(50);
+  private _devicePositionBusy = false;
   /** Wall-thickness tool dialog (docs/WALL-THICKNESS.md). */
   private _wallDialog: {
     a: number[]; b: number[];
@@ -2401,6 +2427,7 @@ export class HouseplanCard extends LitElement {
   };
 
   private _drag: { id: string; sx: number; sy: number; ox: number; oy: number; moved: boolean } | null = null;
+  private _deviceDrag: DeviceDragState | null = null;
   private _rlResize: { id: string; space: string; k0: number; cx: number; cy: number; d0: number } | null = null;
   private _holdTimer?: number;
   private _holdFired = false;
@@ -2642,6 +2669,7 @@ export class HouseplanCard extends LitElement {
     this._bootTimer = undefined; // AUD-1552-01: a cleared id must not block the reconnect watcher
     clearTimeout(this._bootSoftTimer);
     this._saveConfigDebounced.flush(); // never leave an edit unsent on teardown
+    this._cancelDeviceDrag();
     window.removeEventListener('hashchange', this._onHashChange);
     this._labsUnsub?.();
     this._labsUnsub = undefined;
@@ -2813,6 +2841,24 @@ export class HouseplanCard extends LitElement {
       }
       return;
     }
+    if (this._mode === 'devices') {
+      if ((undo || redo) && inField) return;
+      if (redo) {
+        e.preventDefault();
+        this._redoDevicePosition();
+        return;
+      }
+      if (undo) {
+        e.preventDefault();
+        this._undoDevicePosition();
+        return;
+      }
+      if (e.key === 'Escape' && this._deviceDrag) {
+        e.preventDefault();
+        this._cancelDeviceDrag();
+      }
+      return;
+    }
     if (!this._markup) return;
     if ((undo || redo) && inField) return; // keep native text-field history
     if ((e.key === 'Delete' || e.key === 'Backspace') && this._physicalSel
@@ -3810,6 +3856,7 @@ export class HouseplanCard extends LitElement {
     this._pinchStart = null;
     this._swipeStart = null;
     this._drag = null;
+    this._deviceDrag = null;
     this._rlResize = null;
     this._vacFit = null;
     this._compassDrag = false;
@@ -3817,6 +3864,7 @@ export class HouseplanCard extends LitElement {
     this._mode = 'view';
     this._clearGeometryGesture();
     this._geometryHistory.clear();
+    this._devicePositionHistory.clear();
     this._resumeDraftBySpace = {};
     this._tip = null;
     this._hoverRoom = null;
@@ -4045,6 +4093,8 @@ export class HouseplanCard extends LitElement {
       // A genuinely different baseline invalidates local geometry undo. A
       // reconnect echo with identical content deliberately does not.
       this._geometryHistory.clear();
+      this._devicePositionHistory.clear();
+      this._cancelDeviceDrag();
       this._pendingPhysicalWrites.clear();
       if (this._serverCfg) this._clearGeometryGesture();
       this._serverCfg = nextConfig;
@@ -4073,6 +4123,8 @@ export class HouseplanCard extends LitElement {
       layoutChanged = nextLayoutFingerprint !== (this._layoutContentFingerprint
         || contentFingerprint(this._layout));
       if (layoutChanged) {
+        this._devicePositionHistory.clear();
+        this._cancelDeviceDrag();
         this._layout = nextLayout;
         this._layoutContentFingerprint = nextLayoutFingerprint;
       }
@@ -4741,12 +4793,18 @@ export class HouseplanCard extends LitElement {
       const resp = await this.hass.callWS({ type: 'houseplan/layout/get' });
       const remote = resp?.layout || {};
       const merged: Record<string, any> = { ...remote };
-      for (const [id, pos] of mine) merged[id] = pos;
-      const fingerprint = contentFingerprint(merged);
-      if (fingerprint !== (this._layoutContentFingerprint || contentFingerprint(this._layout))) {
-        this._layout = merged;
-        this._layoutContentFingerprint = fingerprint;
+      for (const [id, pos] of mine) {
+        if (pos === null) delete merged[id];
+        else merged[id] = pos;
       }
+      const fingerprint = contentFingerprint(merged);
+      const differsFromCurrent = fingerprint !== contentFingerprint(this._layout);
+      if (differsFromCurrent) {
+        this._cancelDeviceDrag();
+        this._devicePositionHistory.clear();
+        this._layout = merged;
+      }
+      this._layoutContentFingerprint = fingerprint;
       this._layoutRev = resp?.rev ?? this._layoutRev;
       this._canOptimizeUndo = !!resp?.can_optimize_undo;
       this._haIntegrationVersion = typeof resp?.integration_version === 'string'
@@ -4764,7 +4822,12 @@ export class HouseplanCard extends LitElement {
 
   private _dirtyPos = new Set<string>();
   /** Positions sent to the server and not acknowledged yet (HP-1461-02). */
-  private _sentPos = new Map<string, { s?: string; x: number; y: number }>();
+  private _sentPos = new Map<string, DeviceLayout[string] | null>();
+
+  private _persistLocalLayout(): void {
+    this._layout = canonicalizeLayoutGeometry(this._layout);
+    localStorage.setItem(LS_KEY, JSON.stringify(this._layout));
+  }
 
   private _persistLayout = debounce(() => {
     if (this._serverStorage) {
@@ -4786,8 +4849,7 @@ export class HouseplanCard extends LitElement {
       }
       this._cacheSnapshot();
     } else {
-      this._layout = canonicalizeLayoutGeometry(this._layout);
-      localStorage.setItem(LS_KEY, JSON.stringify(this._layout));
+      this._persistLocalLayout();
     }
   }, 600);
 
@@ -4850,8 +4912,10 @@ export class HouseplanCard extends LitElement {
           || this._devices.find((d) => d.id === this._infoCard?.id)?.bindingStatus?.kind === 'ha_disabled') {
         this._closeInfoCard();
       }
-      if (this._drag && this._devices.find((d) => d.id === this._drag!.id)?.bindingStatus?.kind === 'ha_disabled') {
-        this._drag = null;
+      if (this._deviceDrag
+          && this._devices.find((d) => d.id === this._deviceDrag!.id)?.bindingStatus?.kind === 'ha_disabled') {
+        this._cancelDeviceDrag();
+        this._devicePositionHistory.clear();
       }
       clearTimeout(this._holdTimer);
       this._holdFired = false;
@@ -4998,24 +5062,135 @@ export class HouseplanCard extends LitElement {
     return snapPt(spaceCenter(s));
   }
 
+  private _devicePlacementForCanvas(d: DevItem, x: number, y: number): DevicePlacement {
+    if (!this._norm) return { x: Math.round(x), y: Math.round(y) };
+    const g = this._gridPitch;
+    const gx = Math.round(x / g) * g;
+    const gy = Math.round(y / g) * g;
+    return {
+      s: d.space,
+      x: clampCanvasN(gx / NORM_W),
+      y: clampCanvasN(gy / NORM_W),
+    };
+  }
+
+  private _previewDevicePlacement(deviceId: string, placement: DevicePlacement | null): void {
+    this._layout = applyDevicePlacement(this._layout, deviceId, placement);
+    this.requestUpdate();
+  }
+
+  /** Abort an uncommitted device preview. Returns true when a drag existed. */
+  private _cancelDeviceDrag(): boolean {
+    const drag = this._deviceDrag;
+    if (!drag) return false;
+    this._deviceDrag = null;
+    try {
+      if (drag.source?.hasPointerCapture?.(drag.pointerId)) {
+        drag.source.releasePointerCapture(drag.pointerId);
+      }
+    } catch {
+      // Pointer capture may already have ended before the cancellation signal.
+    }
+    this._previewDevicePlacement(drag.id, drag.before);
+    return true;
+  }
+
+  /** One serial, point-wise position write used by drag commit and history. */
+  private async _persistDevicePlacement(
+    deviceId: string,
+    placement: DevicePlacement | null,
+  ): Promise<void> {
+    this._layout = applyDevicePlacement(this._layout, deviceId, placement);
+    if (this._serverStorage) {
+      let pending: DeviceLayout[string] | null = null;
+      let registered = false;
+      try {
+        let response: unknown;
+        if (placement === null) {
+          pending = null;
+          this._sentPos.set(deviceId, pending);
+          registered = true;
+          response = await this.hass.callWS({
+            type: 'houseplan/layout/delete', device_id: deviceId,
+          });
+        } else {
+          const pos = canonicalizePosition(this._layout[deviceId]);
+          pending = pos;
+          this._sentPos.set(deviceId, pending);
+          registered = true;
+          response = await this.hass.callWS({
+            type: 'houseplan/layout/update', device_id: deviceId, pos,
+          });
+        }
+        this._noteLayoutRev(response);
+        this._layoutContentFingerprint = contentFingerprint(this._layout);
+        this._cacheSnapshot();
+      } finally {
+        if (registered && this._sentPos.get(deviceId) === pending) this._sentPos.delete(deviceId);
+      }
+      return;
+    }
+    this._persistLocalLayout();
+  }
+
+  private _devicePositionStateValid(state: DevicePositionState): boolean {
+    const device = this._devices.find((candidate) => candidate.id === state.deviceId);
+    return !!device
+      && device.space === state.spaceId
+      && device.bindingStatus?.kind !== 'ha_disabled'
+      && !!this._spaceModelById(state.spaceId);
+  }
+
+  private async _runDevicePositionHistory(direction: 'undo' | 'redo'): Promise<void> {
+    if (this._cancelDeviceDrag() || this._devicePositionBusy) return;
+    const command = direction === 'undo'
+      ? this._devicePositionHistory.undo()
+      : this._devicePositionHistory.redo();
+    if (!command) return;
+    const target = direction === 'undo' ? command.before : command.after;
+    if (!this._devicePositionStateValid(target)) {
+      this._devicePositionHistory.clear();
+      this._showToast(this._t('history.device_stale'));
+      this.requestUpdate();
+      return;
+    }
+
+    const rollback = devicePlacement(this._layout, target.deviceId);
+    if (target.spaceId !== this._space) {
+      this._commitSpace(target.spaceId);
+      this._restoreZoom();
+    }
+    this._devicePositionBusy = true;
+    this._previewDevicePlacement(target.deviceId, target.placement);
+    try {
+      await this._persistDevicePlacement(target.deviceId, target.placement);
+      this._showToast(this._t(direction === 'undo' ? 'history.undone' : 'history.redone', {
+        name: command.name,
+      }));
+    } catch (error: unknown) {
+      this._previewDevicePlacement(target.deviceId, rollback);
+      if (direction === 'undo') this._devicePositionHistory.redo();
+      else this._devicePositionHistory.undo();
+      this._showToast(this._t('toast.pos_save_failed', { err: this._errText(error) }));
+    } finally {
+      this._devicePositionBusy = false;
+      this.requestUpdate();
+    }
+  }
+
+  private _undoDevicePosition(): void {
+    void this._runDevicePositionHistory('undo');
+  }
+
+  private _redoDevicePosition(): void {
+    void this._runDevicePositionHistory('redo');
+  }
+
   private _savePos(d: DevItem, x: number, y: number): void {
     if (!this._spaceModelById(d.space)) return;
-    if (this._norm) {
-      // The icon center snaps to the nodes of the same grid as the room markup
-      // (docs/CANVAS.md §9). UX-05 has no free-position escape hatch.
-      const g = this._gridPitch;
-      const gx = Math.round(x / g) * g;
-      const gy = Math.round(y / g) * g;
-
-      const prevK = (this._layout[d.id] as any)?.k;
-      this._layout = {
-        ...this._layout,
-        [d.id]: { s: d.space, x: clampCanvasN(gx / NORM_W), y: clampCanvasN(gy / NORM_W),
-          ...(prevK ? { k: prevK } : {}) },
-      };
-    } else {
-      this._layout = { ...this._layout, [d.id]: { x: Math.round(x), y: Math.round(y) } };
-    }
+    this._layout = applyDevicePlacement(
+      this._layout, d.id, this._devicePlacementForCanvas(d, x, y),
+    );
     this._dirtyPos.add(d.id);
     this._persistLayout();
   }
@@ -5191,7 +5366,7 @@ export class HouseplanCard extends LitElement {
     // if a future CSS change accidentally makes a marker a hit target again.
     if (this._mode !== 'view' && this._mode !== 'devices') return;
     ev.stopPropagation();
-    if (this._drag?.moved || this._suppressClick || this._holdFired) return;
+    if (this._deviceDrag?.moved || this._suppressClick || this._holdFired) return;
     if (this._mode === 'devices') {
       this._openMarkerDialog(d);
       return;
@@ -6103,7 +6278,7 @@ export class HouseplanCard extends LitElement {
       }
     }
     // do not interfere with icon and label dragging
-    if (this._drag) return;
+    if (this._drag || this._deviceDrag) return;
     if (this._markup) {
       // Drawing is CLICK-based, so gestures coexist with it: a finger that
       // MOVES pans, two fingers pinch, and _suppressClick keeps the release
@@ -6370,26 +6545,44 @@ export class HouseplanCard extends LitElement {
     }
     // A disabled ghost is a service entry point, not a movable plan object.
     // Leave the click intact so the settings dialog still opens.
-    if (d.bindingStatus?.kind === 'ha_disabled') return;
+    if (d.bindingStatus?.kind === 'ha_disabled' || this._devicePositionBusy) return;
+    if (this._deviceDrag) {
+      if (this._deviceDrag.pointerId !== ev.pointerId) this._cancelDeviceDrag();
+      return;
+    }
     ev.preventDefault();
     const p = this._pos(d);
-    this._drag = { id: d.id, sx: ev.clientX, sy: ev.clientY, ox: p.x, oy: p.y, moved: false };
+    this._deviceDrag = {
+      id: d.id,
+      spaceId: d.space,
+      displayName: d.name,
+      pointerId: ev.pointerId,
+      source: ev.currentTarget as Element | null,
+      sx: ev.clientX,
+      sy: ev.clientY,
+      ox: p.x,
+      oy: p.y,
+      moved: false,
+      before: devicePlacement(this._layout, d.id),
+      start: this._devicePlacementForCanvas(d, p.x, p.y),
+    };
     capturePointer(ev);
     this._tip = null;
   }
 
   private _pointerMove(ev: PointerEvent, d: DevItem): void {
     if (this._mode !== 'devices') return;
-    if (!this._drag || this._drag.id !== d.id) return;
+    const drag = this._deviceDrag;
+    if (!drag || drag.id !== d.id || drag.pointerId !== ev.pointerId) return;
     const stage = this.renderRoot.querySelector('.stage') as HTMLElement;
     if (!stage) return;
     const vb = this._baseVb();
     const rect = stage.getBoundingClientRect();
     const v = this._viewOr(vb);
-    const dx = ((ev.clientX - this._drag.sx) / rect.width) * v.w;
-    const dy = ((ev.clientY - this._drag.sy) / rect.height) * v.h;
-    if (Math.abs(ev.clientX - this._drag.sx) + Math.abs(ev.clientY - this._drag.sy) > 3) {
-      this._drag.moved = true;
+    const dx = ((ev.clientX - drag.sx) / rect.width) * v.w;
+    const dy = ((ev.clientY - drag.sy) / rect.height) * v.h;
+    if (Math.abs(ev.clientX - drag.sx) + Math.abs(ev.clientY - drag.sy) > 3) {
+      drag.moved = true;
       clearTimeout(this._holdTimer);
     }
     // DEV-B58-01. This used to be clamped into `vb` — the CONTENT FRAME — with
@@ -6399,21 +6592,54 @@ export class HouseplanCard extends LitElement {
     // where the new room was going to be. The plan has no edges any more
     // (docs/CANVAS.md §9); the only bound is the garbage limit the backend
     // enforces, and it is the SAME ±5000 on both sides of the wire.
-    const nx = clampCanvasR(this._drag.ox + dx);
-    const ny = clampCanvasR(this._drag.oy + dy);
-    this._savePos(d, nx, ny);
+    const nx = clampCanvasR(drag.ox + dx);
+    const ny = clampCanvasR(drag.oy + dy);
+    this._previewDevicePlacement(d.id, this._devicePlacementForCanvas(d, nx, ny));
   }
 
-  private _pointerUp(_ev: PointerEvent, d: DevItem): void {
+  private _pointerUp(ev: PointerEvent, d: DevItem): void {
     clearTimeout(this._holdTimer);
     if (this._mode !== 'devices') return;
-    if (!this._drag || this._drag.id !== d.id) return;
-    const moved = this._drag.moved;
-    this._drag = moved ? this._drag : null;
-    if (moved) {
-      this._selId = d.id;
-      window.setTimeout(() => (this._drag = null), 0);
+    const drag = this._deviceDrag;
+    if (!drag || drag.id !== d.id || drag.pointerId !== ev.pointerId) return;
+    this._deviceDrag = null;
+    const after = devicePlacement(this._layout, d.id);
+    if (!drag.moved || after === null || sameDevicePlacement(after, drag.start)) {
+      this._previewDevicePlacement(d.id, drag.before);
+      return;
     }
+
+    this._selId = d.id;
+    this._suppressClick = true;
+    window.setTimeout(() => { this._suppressClick = false; }, 0);
+    this._devicePositionBusy = true;
+    this.requestUpdate();
+    void this._persistDevicePlacement(d.id, after)
+      .then(() => {
+        const name = this._t('history.device_move', { name: drag.displayName });
+        this._devicePositionHistory.push({
+          name,
+          before: {
+            deviceId: drag.id, spaceId: drag.spaceId, placement: drag.before,
+          },
+          after: {
+            deviceId: drag.id, spaceId: drag.spaceId, placement: after,
+          },
+        });
+      })
+      .catch((error: unknown) => {
+        this._previewDevicePlacement(d.id, drag.before);
+        this._showToast(this._t('toast.pos_save_failed', { err: this._errText(error) }));
+      })
+      .finally(() => {
+        this._devicePositionBusy = false;
+        this.requestUpdate();
+      });
+  }
+
+  private _pointerCancel(ev: PointerEvent, d: DevItem): void {
+    if (this._deviceDrag?.id !== d.id || this._deviceDrag.pointerId !== ev.pointerId) return;
+    this._cancelDeviceDrag();
   }
 
   private _showToast(msg: string): void {
@@ -6576,7 +6802,7 @@ export class HouseplanCard extends LitElement {
   ): void {
     this._notePointer(ev);
     if (!this._pointerModality.hoverEnabled) return;
-    if (this._drag) return;
+    if (this._drag || this._deviceDrag) return;
     this._tip = { x: ev.clientX, y: ev.clientY, title, meta, lqi, temp, hum };
   }
 
@@ -11804,7 +12030,8 @@ export class HouseplanCard extends LitElement {
         this._showTip(e, d.name, presentation.haDisabled ? ghostLabel : metrics);
       }}
       @pointerup=${(e: PointerEvent) => this._pointerUp(e, d)}
-      @pointercancel=${(e: PointerEvent) => this._pointerUp(e, d)}
+      @pointercancel=${(e: PointerEvent) => this._pointerCancel(e, d)}
+      @lostpointercapture=${(e: PointerEvent) => this._pointerCancel(e, d)}
     >
       ${renderDeviceFace(presentation, {
         surface: 'interactive-plan',
@@ -12127,8 +12354,8 @@ export class HouseplanCard extends LitElement {
       }
       return null;
     }
-    if (this._mode === 'devices' && this._drag?.moved) {
-      const d = this._devices.find((x) => x.id === this._drag!.id);
+    if (this._mode === 'devices' && this._deviceDrag?.moved) {
+      const d = this._devices.find((x) => x.id === this._deviceDrag!.id);
       return d ? (() => { const p = this._pos(d); return [p.x, p.y]; })() : null;
     }
     if (this._mode === 'decor') {

src/houseplan-editor-runtime.ts

@@ -245,6 +245,7 @@ import { enqueueSerializedWrite } from './serialized-write-queue';
 import { hasTranslation, langOf, t, type I18nKey } from './i18n';
 import { classifyPlanFile, encodePlanFile, renderBackdropGuard } from './backdrop-pick';
 import { CommandStack } from './command-stack';
+import type { DeviceLayout, DevicePositionState } from './device-position-history';
 import { resolvedSvgScreenBlend, svgScreenBlendSupported } from './glow-blend';
 import {
   CONTINUITY_LONG_HIDDEN_MS,
@@ -854,6 +855,7 @@ export interface HouseplanEditorHostPort {
   _canEdit: boolean;
   _canOptimizeUndo: boolean;
   _cancelDevicePressFeedback: () => void;
+  _cancelDeviceDrag: () => boolean;
   _cancelModeTransition: (commitTarget?: boolean) => void;
   _candidateDeviceSnapshot: RenderDeviceSnapshot | null;
   _capturedSnapshotConfigEpoch: number;
@@ -898,6 +900,8 @@ export interface HouseplanEditorHostPort {
   _deviceInboxMemo: { key: string; rows: DeviceInboxRow[]; } | null;
   _deviceInboxReturn: DeviceInboxDialogState | null;
   _devicePresentation: (d: DevItem, showLqi?: boolean, designPreview?: boolean) => ResolvedDevicePresentation;
+  _devicePositionBusy: boolean;
+  _devicePositionHistory: CommandStack<DevicePositionState>;
   _devices: DevItem[];
   _dirtyPos: Set<string>;
   _display: (url: string | null | undefined) => string;
@@ -963,7 +967,7 @@ export interface HouseplanEditorHostPort {
   _kioskScale: { icon: number; font: number; };
   _labsIso: boolean;
   _lastValidStageSize: [number, number] | null;
-  _layout: Record<string, { x: number; y: number; s?: string; k?: number; }>;
+  _layout: DeviceLayout;
   _layoutRev: number;
   _logicalViewCenter: (projection: "flat" | "iso") => { x: number; y: number; } | null;
   _markerDialog: { devId?: string; uploadId?: string; name: string; binding: string; bindingMode: "virtual" | "ha"; bindingOpen: boolean; showEntities: boolean; bindingFilter: string; icon: string; autoIcon: string; display: DeviceDisplayMode; rippleColor: string; rippleSize: number; size: number; angle: number; tapAction: string; tapActionTouched: boolean; originalHasTapAction: boolean; originalTapAction: string | null | undefined; tapHintAnnouncement: string; toggleEntity: string; toggleEntityTouched: boolean; originalHasToggleEntity: boolean; originalToggleEntity: string | null | undefined; tapTarget: string; tapConfirm: boolean; runFilter: string; controls: string[]; controlsFilter: string; glowRadius: string; lightRole: "auto" | "always" | "never"; lightRoleTouched: boolean; originalHasIsLight: boolean; originalIsLight: boolean | null | undefined; lightEntity: string; lightEntityTouched: boolean; originalHasLightEntity: boolean; originalLightEntity: string | null | undefined; glowMode: "auto" | "color" | "fixed"; glowColor: string; glowBrightness: number; glowColorDrafted: boolean; glowBrightnessDrafted: boolean; glowTouched: boolean; originalHasGlowColor: boolean; originalGlowColor: { c: string; bri?: number | null; } | null | undefined; valueBadgeEnabled: boolean; valueBadgeSource: ValueBadgeSource | null; valueBadgePosition: ValueBadgePosition; valueBadgeTouched: boolean; originalHasValueBadge: boolean; originalValueBadge: MarkerValueBadge | null | undefined; valueSource: ValueBadgeSource | null; valueSourceTouched: boolean; originalHasValueSource: boolean; originalValueSource: ValueBadgeSource | null | undefined; useClimateTemp: boolean; model: string; link: string; description: string; pdfs: PdfRef[]; room: string; hideFromPlan: boolean; busy: boolean; } | null;
@@ -1052,6 +1056,7 @@ export interface HouseplanEditorHostPort {
     ResizePreview, ResizeLiveLabel[], SpaceGeometryState, ResizeWallUnion, ResizeWallArtifact
   >;
   _restoreZoom: () => void;
+  _redoDevicePosition: () => void;
   _resumeDraftBySpace: Record<string, string>;
   _rlResize: { id: string; space: string; k0: number; cx: number; cy: number; d0: number; } | null;
   _roomCenter: (r: RoomCfg) => number[];
@@ -1075,7 +1080,7 @@ export interface HouseplanEditorHostPort {
   _screenToVb: (sx: number, sy: number) => number[];
   _segments: number[][];
   _selId: string | null;
-  _sentPos: Map<string, { s?: string; x: number; y: number; }>;
+  _sentPos: Map<string, DeviceLayout[string] | null>;
   _serverCfg: ServerConfig | null;
   _serverStorage: boolean;
   _settings: { exclude_integrations?: string[]; group_lights?: boolean; show_all?: boolean; filter_seeded?: boolean; icon_rules?: { pattern: string; icon: string; }[]; };
@@ -1097,6 +1102,7 @@ export interface HouseplanEditorHostPort {
   _suppressClick: boolean;
   _swipeStart: { x: number; y: number; id: number; } | null;
   _t: (key: I18nKey, vars?: Record<string, string | number>) => string;
+  _undoDevicePosition: () => void;
   _thickWallCuts: () => number[][];
   _tip: { x: number; y: number; title: string; meta: string; lqi?: number | null; temp?: number | null; hum?: number | null; } | null;
   _toggleConfirmationLines: (intent: ResolvedToggleIntent) => string[];
@@ -1212,6 +1218,7 @@ public _setMode(mode: 'view' | 'plan' | 'devices' | 'decor', animate = true): vo
       }
       return;
     }
+    if (this.host._mode === 'devices') this.host._cancelDeviceDrag();
     this.host._bootSoftCancel(); // navigation owns its own short, bounded transition
     if ((mode === 'plan' || mode === 'decor') && !this.host._norm) {
       this.host._showToast(this.host._t('toast.markup_needs_server'));
@@ -8315,6 +8322,8 @@ public async _saveMarker(): Promise<void> {
           .catch(() => undefined); // leftovers are harmless; broken links are not
       }
       this._closeMarkerDialog();
+      this.host._cancelDeviceDrag();
+      this.host._devicePositionHistory.clear();
       this.host._regSignature = '';
       this.host._maybeRebuildDevices();
       this.host._showToast(this.host._t('toast.marker_saved'));
@@ -8377,6 +8386,8 @@ public async _deleteMarker(): Promise<void> {
         this.host._deviceInboxReturn = { ...this.host._deviceInboxReturn, tab: 'readd', anchor: binding };
       }
       this._closeMarkerDialog();
+      this.host._cancelDeviceDrag();
+      this.host._devicePositionHistory.clear();
       if (this.host._infoCard?.id === targetId) this.host._closeInfoCard();
       if (this.host._selId === targetId) this.host._selId = null;
       if (this.host._drag?.id === targetId) this.host._drag = null;
@@ -9127,6 +9138,8 @@ public async _runAlignToGrid(): Promise<void> {
       this.host._serverCfg = d.config;
       this.host._layout = d.layout;
       this.host._geometryHistory.clear();
+      this.host._cancelDeviceDrag();
+      this.host._devicePositionHistory.clear();
       this.host._cfgRev = resp?.config_rev ?? this.host._cfgRev + 1;
       this.host._layoutRev = resp?.layout_rev ?? this.host._layoutRev + 1;
       this.host._canOptimizeUndo = !!resp?.can_undo;
@@ -9187,6 +9200,8 @@ public async _undoPlanOptimization(): Promise<void> {
       this.host._cfgRev = cfgResp?.rev ?? this.host._cfgRev;
       this.host._layout = layResp?.layout || this.host._layout;
       this.host._geometryHistory.clear();
+      this.host._cancelDeviceDrag();
+      this.host._devicePositionHistory.clear();
       this.host._layoutRev = layResp?.rev ?? this.host._layoutRev;
       this.host._canOptimizeUndo = false;
       this.host._undoKind = null;
@@ -11741,6 +11756,14 @@ public _renderMarkupBar(): TemplateResult {
   }
 
 public _renderDevicesBar(): TemplateResult {
+    const undoName = this.host._devicePositionHistory.undoName;
+    const redoName = this.host._devicePositionHistory.redoName;
+    const undoTitle = undoName
+      ? this.host._t('history.undo_named', { name: undoName })
+      : this.host._t('history.undo_empty');
+    const redoTitle = redoName
+      ? this.host._t('history.redo_named', { name: redoName })
+      : this.host._t('history.redo_empty');
     return html`<div class="editbar devbar">
       <div class="editbar-tools" tabindex="-1" ?inert=${this.host._modeTransitionBusy}>
         <ha-icon icon="mdi:tune-variant" class="warn"></ha-icon>
@@ -11758,6 +11781,18 @@ public _renderDevicesBar(): TemplateResult {
         ${this.host._editorToolbarGroups.map((group) => this._renderEditorGroupLauncher(group))}
       </div>
       <div class="editbar-end">
+        <button class="btn ghost" data-device-position-history="undo"
+          @click=${() => this.host._undoDevicePosition()}
+          ?disabled=${this.host._devicePositionBusy || !undoName}
+          title=${undoTitle} aria-label=${undoTitle}>
+          <ha-icon icon="mdi:undo-variant" aria-hidden="true"></ha-icon>
+        </button>
+        <button class="btn ghost" data-device-position-history="redo"
+          @click=${() => this.host._redoDevicePosition()}
+          ?disabled=${this.host._devicePositionBusy || !redoName}
+          title=${redoTitle} aria-label=${redoTitle}>
+          <ha-icon icon="mdi:redo-variant" aria-hidden="true"></ha-icon>
+        </button>
         <button class="btn barclose" title=${this.host._t('title.close_editor')}
           data-editor-navigation="view"
           @click=${() => this._setMode('view')}>

src/i18n/de.json

@@ -126,6 +126,8 @@
   "history.decor_transform": "Dekorobjekt transformieren",
   "history.decor_delete": "Dekorobjekt löschen",
   "history.backdrop_transform": "Plan-Hintergrund transformieren",
+  "history.device_move": "{name} verschieben",
+  "history.device_stale": "Der Positionsverlauf ist nicht mehr anwendbar und wurde gelöscht",
   "opening.new": "Neue Öffnung",
   "opening.edit": "Öffnung",
   "opening.door": "Tür",

src/i18n/en.json

@@ -126,6 +126,8 @@
   "history.decor_transform": "Transform decor object",
   "history.decor_delete": "Delete decor object",
   "history.backdrop_transform": "Transform plan backdrop",
+  "history.device_move": "Move {name}",
+  "history.device_stale": "Device position history is no longer applicable and was cleared",
   "opening.new": "New opening",
   "opening.edit": "Opening",
   "opening.door": "Door",

src/i18n/fr.json

@@ -126,6 +126,8 @@
   "history.decor_transform": "Transformer l’objet décoratif",
   "history.decor_delete": "Supprimer l’objet décoratif",
   "history.backdrop_transform": "Transformer l’arrière-plan du plan",
+  "history.device_move": "Déplacer {name}",
+  "history.device_stale": "L’historique des positions n’est plus applicable et a été effacé",
   "opening.new": "Nouvelle ouverture",
   "opening.edit": "Ouverture",
   "opening.door": "Porte",

src/i18n/ru.json

@@ -126,6 +126,8 @@
   "history.decor_transform": "Трансформация объекта декора",
   "history.decor_delete": "Удаление объекта декора",
   "history.backdrop_transform": "Трансформация подложки плана",
+  "history.device_move": "Перемещение: {name}",
+  "history.device_stale": "История позиций больше неприменима и была очищена",
   "opening.new": "Новый проём",
   "opening.edit": "Проём",
   "opening.door": "Дверь",