fix(pwa): Reload-Loop beim Zombie-Cleanup beseitigt

Der Commit 1bec054 hatte einen globalen controllerchange-Listener in
init(), der bei jedem Event location.reload() auslöste. In Kombination
mit der Zombie-Aufräumung (silent SKIP_WAITING) ergab das einen
Endlos-Loop: Seite lädt → Zombie erkannt → SKIP_WAITING → controller-
change → Reload → neue Seite mit frischem Zombie → usw.

Fix: Der controllerchange-Listener wird nur noch scoped aus reload()
heraus gesetzt ({ once: true }) — also genau dann, wenn der User auf
„Neu laden" geklickt hat und einen Reload tatsächlich will. Beim
silent Zombie-Cleanup gibt es keinen Listener, die Seite läuft
einfach nahtlos unter dem neuen (funktional identischen) SW weiter.

Regression-Test sichert ab, dass fireControllerChange() nach silent
SKIP_WAITING location.reload() NICHT aufruft.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/unit/pwa-store.test.ts

@@ -27,7 +27,7 @@ type Reg = {
 
 function mountFakeSW(init: Partial<Reg>): {
   registration: Reg;
-  container: { swListeners: Record<string, ((e: Event) => void)[]> };
+  fireControllerChange: () => void;
 } {
   const registration: Reg = {
     active: init.active ?? null,
@@ -36,34 +36,59 @@ function mountFakeSW(init: Partial<Reg>): {
     addEventListener: vi.fn(),
     update: vi.fn().mockResolvedValue(undefined)
   };
-  const swListeners: Record<string, ((e: Event) => void)[]> = {};
+  type Entry = { fn: (e: Event) => void; once: boolean };
+  const listeners: Entry[] = [];
   Object.defineProperty(navigator, 'serviceWorker', {
     configurable: true,
     value: {
       ready: Promise.resolve(registration),
       controller: registration.active,
-      addEventListener: vi.fn((type: string, fn: (e: Event) => void) => {
-        (swListeners[type] ??= []).push(fn);
-      })
+      addEventListener: vi.fn(
+        (type: string, fn: (e: Event) => void, opts?: AddEventListenerOptions | boolean) => {
+          if (type !== 'controllerchange') return;
+          const once = typeof opts === 'object' ? !!opts.once : false;
+          listeners.push({ fn, once });
+        }
+      )
     }
   });
-  return { registration, container: { swListeners } };
+  const fireControllerChange = () => {
+    const snap = [...listeners];
+    for (const e of snap) {
+      e.fn(new Event('controllerchange'));
+      if (e.once) {
+        const i = listeners.indexOf(e);
+        if (i >= 0) listeners.splice(i, 1);
+      }
+    }
+  };
+  return { registration, fireControllerChange };
 }
 
 async function flush(ms = 20): Promise<void> {
   await new Promise((r) => setTimeout(r, ms));
 }
 
+function stubLocationReload(): ReturnType<typeof vi.fn> {
+  const reload = vi.fn();
+  Object.defineProperty(window, 'location', {
+    configurable: true,
+    value: { ...window.location, reload }
+  });
+  return reload;
+}
+
 describe('pwa store', () => {
   beforeEach(() => {
     vi.resetModules();
   });
 
-  it('zombie-waiter (gleiche Version): kein Toast, silent SKIP_WAITING', async () => {
+  it('zombie-waiter (gleiche Version): kein Toast, silent SKIP_WAITING, KEIN Reload', async () => {
     const active = new FakeSW('1776527907402');
     const waiting = new FakeSW('1776527907402');
     waiting.state = 'installed';
-    mountFakeSW({ active, waiting });
+    const { fireControllerChange } = mountFakeSW({ active, waiting });
+    const reload = stubLocationReload();
 
     const { pwaStore } = await import('../../src/lib/client/pwa.svelte');
     await pwaStore.init();
@@ -71,6 +96,12 @@ describe('pwa store', () => {
 
     expect(pwaStore.updateAvailable).toBe(false);
     expect(waiting.postMessage).toHaveBeenCalledWith({ type: 'SKIP_WAITING' });
+    // Kritisch: selbst wenn der Browser nach dem silent SKIP_WAITING
+    // controllerchange feuert, darf kein Auto-Reload passieren — sonst
+    // Endlos-Loop, weil der nächste Seitenaufruf erneut einen Zombie
+    // bekommt.
+    fireControllerChange();
+    expect(reload).not.toHaveBeenCalled();
   });
 
   it('echtes Update (unterschiedliche Version): Toast', async () => {
@@ -108,17 +139,12 @@ describe('pwa store', () => {
     expect(pwaStore.updateAvailable).toBe(false);
   });
 
-  it('reload() postet SKIP_WAITING, reload erst bei controllerchange', async () => {
+  it('reload() postet SKIP_WAITING, reload einmalig bei controllerchange', async () => {
     const active = new FakeSW('v1');
     const waiting = new FakeSW('v2');
     waiting.state = 'installed';
-    const { container } = mountFakeSW({ active, waiting });
-
-    const reload = vi.fn();
-    Object.defineProperty(window, 'location', {
-      configurable: true,
-      value: { ...window.location, reload }
-    });
+    const { fireControllerChange } = mountFakeSW({ active, waiting });
+    const reload = stubLocationReload();
 
     const { pwaStore } = await import('../../src/lib/client/pwa.svelte');
     await pwaStore.init();
@@ -128,41 +154,17 @@ describe('pwa store', () => {
     expect(waiting.postMessage).toHaveBeenCalledWith({ type: 'SKIP_WAITING' });
     expect(reload).not.toHaveBeenCalled();
 
-    container.swListeners['controllerchange']?.forEach((fn) => fn(new Event('controllerchange')));
+    fireControllerChange();
     expect(reload).toHaveBeenCalledTimes(1);
-  });
 
-  it('refreshing-Flag unterdrückt mehrfache Reloads', async () => {
-    const active = new FakeSW('v1');
-    const waiting = new FakeSW('v2');
-    waiting.state = 'installed';
-    const { container } = mountFakeSW({ active, waiting });
-
-    const reload = vi.fn();
-    Object.defineProperty(window, 'location', {
-      configurable: true,
-      value: { ...window.location, reload }
-    });
-
-    const { pwaStore } = await import('../../src/lib/client/pwa.svelte');
-    await pwaStore.init();
-    await flush();
-
-    pwaStore.reload();
-    const fire = () =>
-      container.swListeners['controllerchange']?.forEach((fn) => fn(new Event('controllerchange')));
-    fire();
-    fire();
+    // Nochmal controllerchange → wegen { once: true } kein zweiter Reload.
+    fireControllerChange();
     expect(reload).toHaveBeenCalledTimes(1);
   });
 
   it('reload() ohne waiting-SW ruft location.reload() sofort auf', async () => {
     mountFakeSW({ active: new FakeSW('v1') });
-    const reload = vi.fn();
-    Object.defineProperty(window, 'location', {
-      configurable: true,
-      value: { ...window.location, reload }
-    });
+    const reload = stubLocationReload();
 
     const { pwaStore } = await import('../../src/lib/client/pwa.svelte');
     await pwaStore.init();