fix(editor): a render no longer restarts a failed runtime load (#757)

The lazy-runtime contract (#353) says a non-terminal failure waits for
the next explicit intent and that there are no background retries. But
_renderBody calls ensure() on every repaint while a surface waits for
the editor or onboarding runtime, and to the loader that call was
indistinguishable from an intent. Surfaces the core opens without the
runtime - the kiosk size dialog after a 3 s hold, the floor import
wizard on an empty plan, a dialog a warm remount revives - therefore
turned one failure into a loop: the loader's own state change, the
toast and its expiry, every hass tick repainted, started a new cycle
and showed a new toast every ~3.5 s. A wall tablet whose old hashed
chunks answer 404 after an integration update sat in that loop forever.

EditorRuntimeLoader.ensure takes an intent: the render calls it as
'reconcile'. A reconcile starts the first cycle a surface needs, but
after a non-terminal failure it returns false without loading until an
explicit ensure() - a tab, an opener, _requestMode, "Add space" - has
started a new cycle. Explicit calls, the terminal fingerprint failure,
ready and an in-flight cycle behave as before, for every loader
instance. The card's render lines stay line-neutral.

smoke_lazy_editor_chunk gains the three surfaces offline through their
real paths (a 3 s touch hold on a kiosk card, an empty plan pushed by
the server, General settings revived by a remount): one cycle, one
notice and an idle loader over 8 s, then the Plan tab and "Add space"
heal. On dev: 4 requests / 3 notices, 6 / 2 and 3 / 2. The loader unit
test pins reconcile versus intent; the mutant
render-reconcile-restarts-editor-runtime-cycle is guarded by the smoke.

Issue: #757
User-Visible: yes
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018qZfe7YS4rqEMKoVeS3GKd

src/editor-runtime-loader.ts

@@ -68,10 +68,19 @@ class FingerprintMismatchError extends Error {}
  * keeps returning `false` without importing again. Any other failure (network,
  * parse) reports via `failed` and returns the loader to `idle`, so the NEXT
  * explicit user intent starts a fresh cycle. There are no background retries.
+ *
+ * A render that finds a surface waiting for the runtime is not an intent
+ * (#757): `ensure('reconcile')` starts the first cycle such a surface needs,
+ * but after a non-terminal failure it returns `false` without loading until
+ * an explicit `ensure()` has started a new cycle. Otherwise every repaint —
+ * the loader's own state change, the failure toast and its expiry, each
+ * `hass` tick — would start another cycle and another toast.
  */
 export class EditorRuntimeLoader<Runtime> {
   private _state: EditorRuntimeLoaderState = 'idle';
   private _inFlight: Promise<boolean> | null = null;
+  /** A non-terminal failure waits for the next explicit intent (#757). */
+  private _awaitingIntent = false;
 
   public constructor(private readonly options: EditorRuntimeLoaderOptions<Runtime>) {}
 
@@ -79,10 +88,14 @@ export class EditorRuntimeLoader<Runtime> {
     return this._state;
   }
 
-  public ensure(): Promise<boolean> {
+  /** `intent`: `explicit` — a user action or an opening; `reconcile` — a render
+   *  that finds a surface waiting for the runtime. */
+  public ensure(intent: 'explicit' | 'reconcile' = 'explicit'): Promise<boolean> {
     if (this._state === 'ready') return Promise.resolve(true);
     if (this._state === 'failed') return Promise.resolve(false);
     if (this._inFlight) return this._inFlight;
+    if (intent === 'reconcile' && this._awaitingIntent) return Promise.resolve(false);
+    this._awaitingIntent = false;
     this._setState('loading');
     this._inFlight = this._loadWithRetry().finally(() => {
       this._inFlight = null;
@@ -110,6 +123,7 @@ export class EditorRuntimeLoader<Runtime> {
         if (error instanceof FingerprintMismatchError) sawMismatch = true;
       }
     }
+    this._awaitingIntent = !sawMismatch;
     this._setState(sawMismatch ? 'failed' : 'idle');
     this.options.failed?.(lastError, { terminal: sawMismatch });
     return false;

src/houseplan-card.ts

@@ -10613,10 +10613,10 @@ export class HouseplanCard extends LitElement {
         || this._markerDialog || this._rulesDialog || this._settingsDialog || this._supportDialog
         || this._alignDialog || this._backupExportDialog || this._backupImportDialog
         || this._kioskDialog || this._vacFit || this._vacCalConfirm);
-    if (onboardingRuntimeRequested && !this._onboardingRuntime) {
-      void this._ensureOnboardingRuntime();
+    if (onboardingRuntimeRequested && !this._onboardingRuntime) { // a render reconciles; it is not an intent (#757)
+      void this._onboardingRuntimeLoader.ensure('reconcile');
     }
-    if (editorRuntimeRequested && !this._editorRuntime) void this._ensureEditorRuntime();
+    if (editorRuntimeRequested && !this._editorRuntime) void this._editorRuntimeLoader.ensure('reconcile');
     const model = this._model;
     const diagnostics = this._renderLife.diagnostics(
       this.hass, this._markers, (binding) => this._bindingStatus(binding),