feat(fase-14): PWA auto-update toast (14.1)

Migrate from `registerSW({ immediate: true })` to `useRegisterSW` from
`virtual:pwa-register/svelte`, mirror its `needRefresh` / `offlineReady`
stores into stable layout-local writables, and render a new
`UpdateToast` pill (bottom-center) that surfaces:

  - "New version available" + a "Reload" button that calls
    `updateServiceWorker(true)`
  - "Ready to use offline" (auto-dismiss after 4s) on first install

Adds `[pwa] …` console.info telemetry on register / need-refresh /
apply. Stand-in for the unavailable `updateViaCache: 'none'` runtime
option (RegisterSWOptions doesn't expose it in vite-plugin-pwa 0.21.2):
poll `reg.update()` every 15min, which keeps a too-aggressively-cached
SW file from pinning users on the previous build for up to 24h.

`apps/web/src/global.d.ts` declares the virtual module's surface inline
so svelte-check picks it up without a relative path into node_modules;
the same file pre-declares the Fase-14.3 `__APP_VERSION__` triplet.

PU-01 stubs the registrar via `window.__pwaRegisterStub` (the layout
checks for it before calling the real `useRegisterSW`) so the toast
flow can be driven from a Playwright test without a second build.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

apps/web/src/routes/+layout.svelte

@@ -1,6 +1,7 @@
 <script lang="ts">
 	import '../app.css';
 	import { onMount } from 'svelte';
+	import { writable, type Writable } from 'svelte/store';
 	import { goto } from '$app/navigation';
 	import { page } from '$app/stores';
 	import { getSupabase } from '$lib/supabase';
@@ -18,6 +19,16 @@
 	import { initTheme } from '$lib/theme';
 	import { setLanguageTag } from '$lib/paraglide/runtime';
 	import { detectLanguage } from '$lib/utils/accept-language';
+	import UpdateToast from '$lib/components/UpdateToast.svelte';
+
+	// Fase 14.1: stores driven by `useRegisterSW()` (or by a test stub
+	// injected via window.__pwaRegisterStub). We expose stable writable
+	// proxies that mirror the upstream values — this avoids needing
+	// runes in the (legacy-mode) root layout AND keeps the reference
+	// passed into <UpdateToast /> stable across the dynamic-import gap.
+	const needRefresh: Writable<boolean> = writable(false);
+	const offlineReady: Writable<boolean> = writable(false);
+	let pwaReload: () => void | Promise<void> = () => {};
 
 	onMount(() => {
 		// Fase 9.1: hydrate the theme stores from localStorage and start
@@ -34,11 +45,69 @@
 			(window as unknown as { __sb?: unknown }).__sb = getSupabase();
 		}
 
-		// Fase 6.1: register the PWA service worker. `@vite-pwa/sveltekit` does
-		// not auto-register — the virtual module is a no-op unless called.
-		void import('virtual:pwa-register').then(({ registerSW }) => {
-			registerSW({ immediate: true });
-		});
+		// Fase 14.1: register the PWA service worker via the Svelte-flavoured
+		// virtual module so we get writable stores for needRefresh /
+		// offlineReady (UpdateToast subscribes to them).
+		//
+		// Note on `updateViaCache: 'none'`: the plan asks for this on the
+		// registration. `vite-plugin-pwa` 0.21.2's RegisterSWOptions doesn't
+		// expose it (workbox-window 7 doesn't either). Mitigated below by an
+		// explicit `reg.update()` poll every 15 minutes — covers the worst
+		// case (a stale SW file the browser cached too aggressively) without
+		// downgrading the plugin.
+		//
+		// The `__pwaRegisterStub` window hook lets Playwright inject a fake
+		// registrar without spinning up a second build (PU-01). We mirror
+		// the upstream stores into our stable `needRefresh` / `offlineReady`
+		// writables so the references handed to <UpdateToast/> never change.
+		const pwaUnsubs: Array<() => void> = [];
+		const wirePwaStores = (r: {
+			needRefresh: Writable<boolean>;
+			offlineReady: Writable<boolean>;
+			updateServiceWorker: (reload?: boolean) => Promise<void>;
+		}) => {
+			pwaReload = () => r.updateServiceWorker(true);
+			pwaUnsubs.push(r.needRefresh.subscribe((v) => needRefresh.set(v)));
+			pwaUnsubs.push(r.offlineReady.subscribe((v) => offlineReady.set(v)));
+		};
+		const stub = (window as unknown as {
+			__pwaRegisterStub?: () => {
+				needRefresh: Writable<boolean>;
+				offlineReady: Writable<boolean>;
+				updateServiceWorker: (reload?: boolean) => Promise<void>;
+			};
+		}).__pwaRegisterStub;
+		if (stub) {
+			console.info('[pwa] registered (stub)');
+			wirePwaStores(stub());
+		} else {
+			void import('virtual:pwa-register/svelte').then(({ useRegisterSW }) => {
+				const r = useRegisterSW({
+					immediate: true,
+					onRegisteredSW(swUrl: string, reg: ServiceWorkerRegistration | undefined) {
+						console.info('[pwa] registered', swUrl);
+						// Stand-in for `updateViaCache: 'none'`: poll the SW
+						// for an update every 15 minutes. Without this a
+						// stale cached SW file could keep the user on the
+						// previous build for up to 24h in some browsers.
+						if (reg) {
+							setInterval(() => {
+								reg.update().catch(() => {
+									/* offline / transient */
+								});
+							}, 15 * 60 * 1000);
+						}
+					},
+					onRegisterError(err: unknown) {
+						console.info('[pwa] register error', err);
+					},
+					onNeedRefresh() {
+						console.info('[pwa] update available');
+					}
+				});
+				wirePwaStores(r);
+			});
+		}
 
 		const supabase = getSupabase();
 
@@ -117,6 +186,7 @@
 			collectiveUnsub();
 			void teardownFeatureSubscriptions();
 			clearServerAdminFlag();
+			for (const u of pwaUnsubs) u();
 		};
 	});
 
@@ -209,4 +279,5 @@
 
 <ParaglideJS {i18n}>
 	<slot />
+	<UpdateToast {needRefresh} {offlineReady} onReload={pwaReload} />
 </ParaglideJS>