From f0db83153bd84aba1712ca18044ef258c92a0605 Mon Sep 17 00:00:00 2001
From: Adrian Florescu <florescuadyz@yahoo.com>
Date: Sat, 4 Jul 2026 09:57:49 +0300
Subject: [PATCH 1/3] R5: offline rechecks re-run no effects; presentation
 memoized on (state, title)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

From the post-review refactor plan (plan.md, R5) — the battery-drain
finding. Old e2e untouched and green (37/37); 79/79 unit.

radioMachine: the error state's wait-for-recovery loop moves into
substates (backoff -> offlineRecheck). Entry fx and the sound supervisor
run ONCE per error cycle; an offline recheck only re-arms its own child
timer (reenter on the atomic child leaves the parent alone). Before, every
10s tick re-entered 'error' and re-ran the whole entry pipeline — new
MediaMetadata (lock-screen artwork refetch + widget flicker), 6 action
handlers re-registered, poster img.src reassigned, supervisor interval
torn down and recreated — all night, for as long as the phone sat offline.
The offlineRecheck context flag and its two actions are gone; the cadence
and backoff values are unchanged (the old cadence unit tests pass as-is).

mediaSession: updateMediaSession memoizes the presentation (MediaMetadata,
poster img.src, document.title, loadingMsg) on (state, station title) —
identical consecutive renders are skipped and cloudinaryImageUrl is
computed once instead of twice. Deliberately NOT memoized: action-handler
re-registration and playbackState — iOS resets those out from under us
(d798cc9), so they re-assert on every call, exactly as before.

New unit test pins the phase's point: 50 offline rechecks produce zero new
side-effect calls (mediaSession/sounds/buttons/supervisor), and the loop
still recovers on the first online check.

NEEDS DEVICE SMOKE before merge: phone offline in error 5+ min, locked —
error tone keeps playing, Now Playing widget no longer flickers every 10s;
wifi back on -> recovers to playing by itself.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 src/js/mediaSession.ts   | 30 ++++++++++++-----
 src/js/radioCore.test.ts | 45 ++++++++++++++++++++++++++
 src/js/radioMachine.ts   | 70 ++++++++++++++++++++++++++--------------
 3 files changed, 112 insertions(+), 33 deletions(-)

diff --git a/src/js/mediaSession.ts b/src/js/mediaSession.ts
index 8e63f33..f6911c7 100644
--- a/src/js/mediaSession.ts
+++ b/src/js/mediaSession.ts
@@ -91,6 +91,13 @@ function reassertPlaybackState() {
 loadingNoise.addEventListener('pause', reassertPlaybackState);
 errorNoise.addEventListener('pause', reassertPlaybackState);
 
+// The presentation (metadata, poster, document title) is a pure function of
+// (state, station title) — re-rendering it when neither changed is wasted
+// work (and on iOS it re-fetches lock-screen artwork). Memoize on that key.
+// Handler re-registration and playbackState are deliberately NOT memoized:
+// iOS resets them out from under us (d798cc9), so they re-assert every call.
+let lastRender: { state: RadioState; title: string } | null = null;
+
 export const updateMediaSession = (newState: RadioState) => {
   const title = radioSelect.options[radioSelect.selectedIndex].text;
   const isIdle = newState === 'idle';
@@ -100,13 +107,17 @@ export const updateMediaSession = (newState: RadioState) => {
 
   const idleText = hasRestoredStation ? title : LABELS.appName;
   const displayText = isIdle ? idleText : isLoading ? LABELS.loading : hasError ? LABELS.error : title;
+  const changed = lastRender?.state !== newState || lastRender?.title !== title;
+  const artworkUrl = changed ? cloudinaryImageUrl(displayText, isLive) : '';
 
   if ('mediaSession' in navigator) {
-    navigator.mediaSession.metadata = new MediaMetadata({
-      title: isLoading ? `${LABELS.loading}${title}` : hasError ? `${LABELS.error} la încărcarea ${title}` : isIdle ? idleText : title,
-      artist: `${LABELS.appName}${isIdle && !hasRestoredStation ? '' : ` | ${title}`}`,
-      artwork: [{ src: cloudinaryImageUrl(displayText, isLive) }]
-    });
+    if (changed) {
+      navigator.mediaSession.metadata = new MediaMetadata({
+        title: isLoading ? `${LABELS.loading}${title}` : hasError ? `${LABELS.error} la încărcarea ${title}` : isIdle ? idleText : title,
+        artist: `${LABELS.appName}${isIdle && !hasRestoredStation ? '' : ` | ${title}`}`,
+        artwork: [{ src: artworkUrl }]
+      });
+    }
 
     // Re-register ALL action handlers on every state transition.
     // iOS resets them when a different <audio> element (loading/error sound)
@@ -125,7 +136,10 @@ export const updateMediaSession = (newState: RadioState) => {
     }
   }
 
-  posterImage.querySelector('img')!.src = cloudinaryImageUrl(displayText, isLive);
-  document.title = `${isLoading ? "⏳" : ''} ${hasError ? '❤️‍🩹' : ''} ${isLive ? '🔴' : ''} ${isIdle ? idleText : isLoading ? `${LABELS.loading} ${title}` : hasError ? LABELS.error : title}`;
-  loadingMsg.innerText = isLoading ? `${LABELS.loading} ${title}` : '';
+  if (changed) {
+    posterImage.querySelector('img')!.src = artworkUrl;
+    document.title = `${isLoading ? "⏳" : ''} ${hasError ? '❤️‍🩹' : ''} ${isLive ? '🔴' : ''} ${isIdle ? idleText : isLoading ? `${LABELS.loading} ${title}` : hasError ? LABELS.error : title}`;
+    loadingMsg.innerText = isLoading ? `${LABELS.loading} ${title}` : '';
+  }
+  lastRender = { state: newState, title };
 };
diff --git a/src/js/radioCore.test.ts b/src/js/radioCore.test.ts
index 30b793a..cb2fb85 100644
--- a/src/js/radioCore.test.ts
+++ b/src/js/radioCore.test.ts
@@ -1356,6 +1356,51 @@ describe('system pause vs user pause', () => {
     expect(clock.hasScheduled(RECOVERY_DELAY_MS)).toBe(true);
   });
 
+  it('an offline night in error is quiet work: rechecks re-run NO effects', async () => {
+    let online = true;
+    const { deps, calls } = makeDeps({ isOnline: () => online });
+    deps._setPlayerPlayResult(Promise.reject(new Error('fail')));
+    const { core, clock } = createCore(deps);
+
+    core.playRadio(0);
+    await flushPromises();
+    clock.increment(3000);
+    await flushPromises();
+    expect(core.getState()).toBe('error');
+    online = false;
+
+    // Snapshot every observable side effect after entering error…
+    clock.increment(RECOVERY_DELAY_MS); // land in the fixed-cadence recheck
+    const fxBefore = {
+      mediaSession: calls.mediaSession.length,
+      errorSound: calls.errorSound.length,
+      showButton: calls.showButton.length,
+      supervisors: (deps.setInterval as ReturnType<typeof vi.fn>).mock.calls.length,
+    };
+
+    // …then let a whole offline night of rechecks pass.
+    for (let i = 0; i < 50; i++) {
+      clock.increment(RECOVERY_DELAY_MS);
+      await flushPromises();
+    }
+    expect(core.getState()).toBe('error');
+
+    // The old reenter design re-applied ALL of these every 10s (metadata
+    // rebuild, sound re-assert, supervisor teardown+recreate) — a battery
+    // drain and lock-screen flicker. Now a recheck only re-arms its timer.
+    expect(calls.mediaSession.length).toBe(fxBefore.mediaSession);
+    expect(calls.errorSound.length).toBe(fxBefore.errorSound);
+    expect(calls.showButton.length).toBe(fxBefore.showButton);
+    expect((deps.setInterval as ReturnType<typeof vi.fn>).mock.calls.length).toBe(fxBefore.supervisors);
+
+    // And the recovery loop is still alive: net returns → next check plays.
+    online = true;
+    deps._setPlayerPlayResult(Promise.resolve());
+    clock.increment(RECOVERY_DELAY_MS);
+    await flushPromises();
+    expect(core.getState()).toBe('playing');
+  });
+
   it('an unexpected native pause while online still pauses (interruption, unplugged headphones)', async () => {
     const { deps } = makeDeps();
     const { core, clock } = createCore(deps);
diff --git a/src/js/radioMachine.ts b/src/js/radioMachine.ts
index b4176b5..22208e4 100644
--- a/src/js/radioMachine.ts
+++ b/src/js/radioMachine.ts
@@ -134,9 +134,6 @@ export interface RadioContext {
   recoveryCount: number;
   lastPauseTime: number | null;
   userPauseIntentAt: number | null;
-  /** True while the recovery loop is just re-checking a known-offline network
-   *  (fixed cadence, no backoff escalation, no recoveryCount increment). */
-  offlineRecheck: boolean;
 }
 
 export type RadioEvent =
@@ -168,13 +165,6 @@ export function createRadioMachine(deps: RadioDeps) {
     { target: 'error' as const, actions: [...extra, 'beginErrorCycle' as const] },
   ];
 
-  // Network is back → attempt recovery; still offline → re-check on a fixed
-  // cadence without escalating (nothing was attempted).
-  const tryRecover = [
-    { guard: 'isOnline' as const, target: 'recovering' as const, actions: 'clearOfflineRecheck' as const },
-    { target: 'error' as const, reenter: true, actions: 'markOfflineRecheck' as const },
-  ];
-
   // Live streams drift — resuming after a long pause would replay stale
   // buffer, so restart the station instead, honoring the same offline
   // fast-fail as PLAY (no point trying on a dead network).
@@ -232,15 +222,15 @@ export function createRadioMachine(deps: RadioDeps) {
       LOADING_TIMEOUT: LOADING_TIMEOUT_MS,
       RETRY_DELAY: RETRY_DELAY_MS,
       // Exponential backoff (10s → 20s → … capped), forever — a radio should
-      // never give up. While clearly offline, re-check on a fixed cadence
-      // without escalating (nothing was attempted).
+      // never give up.
       RECOVERY_DELAY: ({ context }) =>
-        context.offlineRecheck
-          ? RECOVERY_DELAY_MS
-          : Math.min(
-              RECOVERY_DELAY_MS * 2 ** Math.min(context.recoveryCount - 1, 6),
-              RECOVERY_DELAY_MAX_MS,
-            ),
+        Math.min(
+          RECOVERY_DELAY_MS * 2 ** Math.min(context.recoveryCount - 1, 6),
+          RECOVERY_DELAY_MAX_MS,
+        ),
+      // While clearly offline, re-check on a fixed cadence without
+      // escalating (nothing was attempted).
+      OFFLINE_RECHECK: RECOVERY_DELAY_MS,
     },
 
     actors: {
@@ -301,11 +291,8 @@ export function createRadioMachine(deps: RadioDeps) {
       // Runs on the TRANSITION into error (not on entry) so the RECOVERY_DELAY
       // expression is guaranteed to see the incremented count.
       beginErrorCycle: assign(({ context }) => ({
-        offlineRecheck: false,
         recoveryCount: context.recoveryCount + 1,
       })),
-      markOfflineRecheck: assign({ offlineRecheck: true }),
-      clearOfflineRecheck: assign({ offlineRecheck: false }),
       markUserPauseIntent: assign(() => ({ userPauseIntentAt: deps.performanceNow() })),
       consumeUserPauseIntent: assign({ userPauseIntentAt: null }),
       markPauseTime: assign(() => ({ lastPauseTime: deps.performanceNow() })),
@@ -336,7 +323,6 @@ export function createRadioMachine(deps: RadioDeps) {
       recoveryCount: 0,
       lastPauseTime: null,
       userPauseIntentAt: null,
-      offlineRecheck: false,
     },
     initial: 'idle',
 
@@ -467,13 +453,47 @@ export function createRadioMachine(deps: RadioDeps) {
       },
 
       error: {
+        // Entry fx and the sound supervisor run ONCE per error cycle — the
+        // wait-for-recovery loop lives in substates so an offline night does
+        // not rebuild MediaMetadata / re-register handlers / re-create the
+        // supervisor every 10 seconds (it used to, via reenter).
         entry: [{ type: 'applyFx', params: { state: 'error' } }],
         invoke: { src: 'soundSupervisor', input: { sound: 'error' } as const },
-        after: {
-          RECOVERY_DELAY: tryRecover,
+        initial: 'backoff',
+        states: {
+          // One escalating backoff wait after a failed attempt.
+          backoff: {
+            after: {
+              RECOVERY_DELAY: [
+                { guard: 'isOnline', target: '#radio.recovering' },
+                { target: 'offlineRecheck' },
+              ],
+            },
+            on: {
+              RETRY_FROM_ERROR: [
+                { guard: 'isOnline', target: '#radio.recovering' },
+                { target: 'offlineRecheck' },
+              ],
+            },
+          },
+          // Clearly offline: re-check on a fixed cadence. The reenter only
+          // re-arms this child's timer — the parent (fx, supervisor) stays.
+          offlineRecheck: {
+            after: {
+              OFFLINE_RECHECK: [
+                { guard: 'isOnline', target: '#radio.recovering' },
+                { target: 'offlineRecheck', reenter: true },
+              ],
+            },
+            on: {
+              RETRY_FROM_ERROR: [
+                { guard: 'isOnline', target: '#radio.recovering' },
+                { target: 'offlineRecheck', reenter: true },
+              ],
+            },
+          },
         },
         on: {
-          RETRY_FROM_ERROR: tryRecover,
           ...startFromSelector,
           PAUSE_REQUESTED: { actions: 'raiseStop' },
         },

From c5e6bc8276aa170ed6b9f62b72f9ee482925a6e0 Mon Sep 17 00:00:00 2001
From: Adrian Florescu <florescuadyz@yahoo.com>
Date: Sat, 4 Jul 2026 10:09:16 +0300
Subject: [PATCH 2/3] Fix the zombie tone: a late-settling carry swap must not
 resurrect after stop
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Device-observed on master (R4b): sometimes the loading tone played UNDER
the live radio — the exact overlapping-sounds class the state machine
exists to forbid. Root cause: carrySound()'s never-trade-audible-for-
silent revert ran in a .catch with NO generation guard. When the swap's
play() settled late (iOS latency) and the machine had meanwhile recovered
to 'playing' (stop already ran: paused, src cleared, isPlaying=false),
the catch reverted the src and RESTARTED the element — and nothing could
stop it again, because isPlaying was already false so every later stop()
skipped it.

The revert now runs only while still wanted: same generation and not an
AbortError (our own stop/reclaim interrupting the pending play). This was
the only unguarded resurrect path in the file — every other catch already
checks the generation.

New unit test pins the repro: stop lands while the swap's play() is in
flight; the late rejection must leave the element dead (no revert, no
restart). 80/80 unit, 37/37 e2e.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 src/js/soundEffects.test.ts | 27 +++++++++++++++++++++++++++
 src/js/soundEffects.ts      | 10 ++++++++--
 2 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/src/js/soundEffects.test.ts b/src/js/soundEffects.test.ts
index f6bb900..80a89d4 100644
--- a/src/js/soundEffects.test.ts
+++ b/src/js/soundEffects.test.ts
@@ -127,6 +127,33 @@ describe('feedback sounds — the tone-swap rule', () => {
     expect(errEl.playCalls).toBe(0);
   });
 
+  it('a stop during a pending tone swap must not resurrect the sound', async () => {
+    // Device-observed zombie: the swap's play() settles LATE (iOS latency),
+    // the stream recovers meanwhile and applyFx('playing') stops the tones —
+    // then the late rejection used to revert-and-restart the element, playing
+    // the loading tone UNDER the live radio, unstoppable (isPlaying already
+    // false, so later stops skipped it).
+    const { loadEl, loading, error } = await makePair();
+
+    loading.play();
+    let rejectSwap!: (e: unknown) => void;
+    loadEl.playResult = new Promise((_, reject) => { rejectSwap = reject; });
+    error.play();            // tone swap onto the live element is in flight
+    loading.stop();
+
+    // The stream recovers: applyFx('playing') stops both tones.
+    loading.stop();
+    error.stop();
+    expect(loadEl.paused).toBe(true);
+
+    // The swap's rejection lands only now.
+    rejectSwap(Object.assign(new Error('denied'), { name: 'NotAllowedError' }));
+    await flushPromises();
+
+    expect(loadEl.paused).toBe(true);           // stays dead
+    expect(loadEl.getAttribute('src')).toBe(''); // no revert, no restart
+  });
+
   it('a user stop silences everything, including a carrying element', async () => {
     const { loadEl, errEl, loading, error } = await makePair();
 
diff --git a/src/js/soundEffects.ts b/src/js/soundEffects.ts
index 94c4f9a..667b92f 100644
--- a/src/js/soundEffects.ts
+++ b/src/js/soundEffects.ts
@@ -255,8 +255,14 @@ export function audioInstance(htmlElement: HTMLAudioElement): SoundInstance {
       carriedSrc = src;
       htmlElement.src = src;
       htmlElement.currentTime = 0;
-      htmlElement.play().catch(() => {
-        // Even the continuation was denied — restore our own sound rather
+      const gen = playGeneration;
+      htmlElement.play().catch((error) => {
+        // The swap failed — but if we were stopped or reclaimed meanwhile
+        // (generation moved on), or our own stop interrupted it (AbortError),
+        // stay silent: restarting here would resurrect a zombie tone UNDER
+        // the live stream (device-observed: loading tone + radio at once).
+        if (gen !== playGeneration || isAbortError(error)) return;
+        // Denied outright while still wanted — restore our own sound rather
         // than trade something audible for silence.
         carriedSrc = null;
         htmlElement.src = ownSrc();

From e2a39a4a4d7d7a255386449a8520d844c0c31136 Mon Sep 17 00:00:00 2001
From: Adrian Florescu <florescuadyz@yahoo.com>
Date: Sat, 4 Jul 2026 10:20:15 +0300
Subject: [PATCH 3/3] =?UTF-8?q?R6:=20startup=20off=20the=20critical=20path?=
 =?UTF-8?q?=20=E2=80=94=20idle-deferred=20image=20precache,=20non-blocking?=
 =?UTF-8?q?=20SW=20writes?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Same PR as R5 + the zombie fix, per Adrian (one PR for everything left).

- main.ts: the ~22 status/station image fetches no longer compete with the
  stream connection and sound-blob preloads at startup — deferred to
  requestIdleCallback (setTimeout fallback for Safari). The precache LIST
  stays complete, deliberately: the untouched e2e (and the product) pin
  all-station posters working offline; only the timing moves.
- sw.js: the app-shell cache.put leaves the response path (event.waitUntil,
  same pattern as the cloudinary branch) — pages get first bytes without
  waiting for a body download + disk write; /downloads/ (the 2.4MB APK) is
  streamed straight through instead of landing in the app cache; APP_CACHE
  bumped to v4 so existing installs evict the cached APK.
- plan.md: R5/R6 statuses + the deliberate deviations from the initial R6
  sketch (full list kept, page-level put kept — first-load SW claim race).

80/80 unit, 37/37 e2e (image tests untouched and green), typecheck clean.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 plan.md          | 19 +++++++++++++++++--
 src/js/main.ts   | 12 ++++++++++--
 src/public/sw.js | 23 ++++++++++++++++++-----
 3 files changed, 45 insertions(+), 9 deletions(-)

diff --git a/plan.md b/plan.md
index 601afd2..7d6a6be 100644
--- a/plan.md
+++ b/plan.md
@@ -600,7 +600,7 @@ offline.
 
 Verificare: typecheck, unit (cu teste noi), e2e neatins.
 
-## Faza R5: recheck offline fara reenter + memoizare updateMediaSession
+## Faza R5: recheck offline fara reenter + memoizare updateMediaSession [in PR #50]
 
 Zona sensibila iOS — ultima faza de logica, cu smoke pe device.
 
@@ -622,7 +622,22 @@ tick-uri), e2e neatins, SMOKE PE DEVICE: telefon offline in error 5+ min cu
 ecranul blocat — widget-ul nu mai palpaie, bateria nu se scurge; revenire
 online → recovering → playing.
 
-## Faza R6: startup mai usor (cloudinary precache)
+## Faza R6: startup mai usor (cloudinary precache) [in PR #50]
+
+Nota de implementare (2026-07-04): la cererea lui Adrian, R5 + fix-ul
+zombie (carrySound cu garda de generatie) + R6 merg intr-UN SINGUR PR
+(#50). Abateri deliberate fata de planul initial al R6:
+- Lista de precache NU se reduce la labels + statia curenta: e2e-ul (si
+  produsul) garanteaza ca posterele TUTUROR posturilor functioneaza
+  offline — reducerea ar fi schimbat comportamentul. Ramane lista
+  completa, doar amanata la requestIdleCallback (fallback setTimeout 3s
+  pe Safari).
+- Pagina isi pastreaza cache.put-ul propriu: pe primul load SW-ul preia
+  controlul abia dupa activate/claim, iar fara put-ul paginii imaginile
+  fetch-uite inainte de claim ar ramane necache-uite.
+- sw.js: put-ul de app-shell iese de pe calea raspunsului (waitUntil, ca
+  la cloudinary), /downloads/ (APK 2.4MB) nu se mai cache-uieste, bump
+  APP_CACHE v4 ca sa evacueze APK-ul din instalarile existente.
 
 - cloudinary.ts/main.ts: amana precacheStatusImages la `requestIdleCallback`
   (fallback setTimeout) si redu la labels + statia curenta (azi: 22 de
diff --git a/src/js/main.ts b/src/js/main.ts
index 83d59a4..81698b9 100644
--- a/src/js/main.ts
+++ b/src/js/main.ts
@@ -28,11 +28,19 @@ declare global {
 
 document.addEventListener("touchstart", function () { }, true);
 
-// Pre-cache status images + station name images for offline use
-precacheStatusImages([
+// Pre-cache status images + station name images for offline use — deferred
+// to idle time so the ~22 image fetches don't compete with the stream
+// connection and the sound-blob preloads at startup (time-to-audio first).
+const runStatusImagePrecache = () => precacheStatusImages([
   ...Object.values(LABELS),
   ...Array.from(radioSelect.options).map(o => o.text),
 ]);
+if ('requestIdleCallback' in window) {
+  requestIdleCallback(runStatusImagePrecache, { timeout: 5000 });
+} else {
+  // Safari has no requestIdleCallback — a plain delay clears startup anyway.
+  setTimeout(runStatusImagePrecache, 3000);
+}
 
 // Restore last station before anything reads selectedIndex
 const restoredStationIndex = getStoredStationIndex(radioSelect.options.length);
diff --git a/src/public/sw.js b/src/public/sw.js
index e323575..20e5ca5 100644
--- a/src/public/sw.js
+++ b/src/public/sw.js
@@ -2,7 +2,7 @@
 // Bump APP_CACHE version when static files change to force re-cache.
 // Bump SOUND_CACHE version when sound files change.
 
-const APP_CACHE_NAME = 'radio-app-v3';
+const APP_CACHE_NAME = 'radio-app-v4'; // v4: the APK no longer lands in the cache
 const CACHE_NAME = 'radio-images-v3';
 const SOUND_CACHE_NAME = 'radio-sounds-v2';
 const MAX_CACHED_IMAGES = 30;
@@ -98,19 +98,32 @@ self.addEventListener('fetch', (event) => {
     return;
   }
 
-  // App shell — network-first, fallback to cache for offline
+  // App shell — network-first, fallback to cache for offline.
+  // The APK download is streamed straight through: 2.4MB has no business
+  // sitting in the app cache, and caching it also delayed the download.
   if (
     event.request.method === 'GET' &&
     reqUrl.origin === self.location.origin &&
-    !reqUrl.pathname.startsWith('/sounds/')
+    !reqUrl.pathname.startsWith('/sounds/') &&
+    !reqUrl.pathname.startsWith('/downloads/')
   ) {
     event.respondWith(
       (async () => {
         try {
           const response = await fetch(event.request);
           if (response.ok) {
-            const cache = await caches.open(APP_CACHE_NAME);
-            await cache.put(event.request, response.clone());
+            // Cache write happens off the response path (same pattern as the
+            // cloudinary branch) — the page gets its first bytes without
+            // waiting for a full body download + disk write.
+            const clone = response.clone();
+            event.waitUntil(
+              (async () => {
+                try {
+                  const cache = await caches.open(APP_CACHE_NAME);
+                  await cache.put(event.request, clone);
+                } catch (_) { /* swallow cache errors */ }
+              })()
+            );
           }
           return response;
         } catch (_) {