fix v1.41.2: uploaded files survive marker rebinding

- new WS houseplan/files/migrate moves /files/<oldId>/ to the new id
  (admin-only, sanitized ids, merge-safe, removes the empty old dir)
- _saveMarker calls it and rewrites pdf urls (migratePdfUrls pure
  helper, +1 unit test, 112) when rebinding changes the id
- field incident: the sauna heater manuals pointed at an orphaned
  old-id folder that got cleaned up; data restored by hand on the
  home instance (official Harvia PDFs re-downloaded)
- TESTING/CHANGELOG same-commit

src/houseplan-card.ts

@@ -14,7 +14,7 @@ import {
 import {
   lqiColor, snapToGrid, samePoint, pointInPolygon, markerIdForBinding,
   segmentCm, formatLength, roomEdges, roomPoly, pointStrictlyInside, roomsOverlap,
-  pointOnBoundary, mergeRooms, splitRoomPath, polygonArea, closestPointOnBoundary, pointStrictlyInside as ptInside, islandsOf, sharedBoundary, openZoneOf, distToSegment, outlineWithout, cutSegments, alignGuides, segmentAngle, is45, type AlignGuide, swipeTarget, clampScale,
+  pointOnBoundary, mergeRooms, splitRoomPath, polygonArea, closestPointOnBoundary, pointStrictlyInside as ptInside, islandsOf, sharedBoundary, openZoneOf, distToSegment, outlineWithout, cutSegments, alignGuides, segmentAngle, is45, type AlignGuide, swipeTarget, clampScale, migratePdfUrls,
   snapToWall, openingAmount,
   averageLqi, fitView, declump, safeUrl, resolveTapAction, floorsOf, type FloorInfo,
   stateIcon, lightColorOf, isAlarmState, parseRoomRef, diffNewDevices, glowColorOf, doorSector, hasRoomBehind, controlsAction, isControllable,
@@ -32,7 +32,7 @@ import './space-card';
 import { cardStyles } from './styles';
 import { langOf, t, type I18nKey } from './i18n';
 
-const CARD_VERSION = '1.41.1';
+const CARD_VERSION = '1.41.2';
 const LS_KEY = 'houseplan_card_layout_v1';
 const LS_CFG = 'houseplan_card_cfg_v1'; // cache of the server config+layout for instant rendering
 const LS_ZOOM = 'houseplan_card_zoom_v1';
@@ -2459,6 +2459,7 @@ class HouseplanCard extends LitElement {
         angle: dlg.angle ? dlg.angle : null,
         tap_action: dlg.tapAction || null,
         controls: dlg.controls.length ? dlg.controls : null,
+        // pdfs may be rewritten below when rebinding changes the marker id
         glow_radius_cm: (() => {
           const v = parseFloat(dlg.glowRadius);
           if (!Number.isFinite(v) || v <= 0) return null;
@@ -2480,6 +2481,15 @@ class HouseplanCard extends LitElement {
       const prevRoomId = prevDev?.marker?.room_id ?? null;
       const roomChanged = !!dlg.room && prevDev != null
         && (prevDev.space !== space || prevDev.area !== area || prevRoomId !== roomId);
+      // rebinding changed the id → move the uploaded files along (server-side)
+      // and rewrite the attached urls; otherwise the old-id folder goes orphan
+      // (that is how the sauna manuals were lost — incident 2026-07-26)
+      if (oldId && oldId !== id && marker.pdfs?.length) {
+        await this.hass
+          .callWS({ type: 'houseplan/files/migrate', from_id: oldId, to_id: id })
+          .catch(() => undefined);
+        marker.pdfs = migratePdfUrls(marker.pdfs, oldId, id);
+      }
       // remove the previous marker (by the old id and by the new id)
       cfg.markers = cfg.markers.filter((m) => m.id !== id && m.id !== oldId);
       cfg.markers.push(marker);

src/logic.ts

@@ -965,6 +965,21 @@ export function outlineWithout(poly: number[][], cuts: number[][], eps = 1e-6):
   return cutSegments(edges, cuts, eps);
 }
 
+// ---------------- marker files ----------------
+
+/**
+ * Rewrite attached-file urls when a marker's id changes (rebinding): the
+ * server moves /files/<oldId>/ to /files/<newId>/, the urls must follow.
+ */
+export function migratePdfUrls<T extends { url: string }>(
+  pdfs: T[], oldId: string, newId: string,
+): T[] {
+  if (!oldId || !newId || oldId === newId) return pdfs;
+  const from = '/files/' + oldId + '/';
+  const to = '/files/' + newId + '/';
+  return pdfs.map((p) => (p.url.includes(from) ? { ...p, url: p.url.split(from).join(to) } : p));
+}
+
 // ---------------- kiosk gestures ----------------
 
 /**