feat(DPoP): UI: bcast events to support multi tab

add also playwright test with the multi tab

frontend/src/lib/api/endpoints/auth.ts

@@ -456,7 +456,6 @@ export async function startOidcLink(): Promise<string> {
 		headers: { ...JSON_HEADERS, ...getCsrfHeaders() },
 		body: '{}'
 	});
-<<<<<<< HEAD
 	if (!res.ok) {
 		const { errorType, message } = await parseErrorBody(res);
 		throw new ApiError(res.status, res.statusText, '/api/auth/oidc/link/start', errorType, message);
@@ -515,8 +514,13 @@ export async function logout(): Promise<LogoutResult> {
 		try {
 			const { clearKeypair } = await import('$lib/auth/dpop');
 			const { clearNonce } = await import('$lib/auth/dpop-proof');
+			const { broadcastSessionCleared } = await import('$lib/auth/session-broadcast');
 			await clearKeypair();
 			clearNonce();
+			// Notify every OTHER tab of this origin that the session is
+			// gone — Gate 8 cross-tab UX. Tabs that were sitting idle
+			// don't have to wait for their next 401 to notice.
+			broadcastSessionCleared();
 		} catch (err) {
 			console.debug('dpop: cleanup failed during logout', err);
 		}

frontend/src/lib/auth/session-broadcast.ts

@@ -0,0 +1,78 @@
+/**
+ * Cross-tab session invalidation via `BroadcastChannel` — the
+ * "logout on tab A, tab B knows immediately" wire.
+ *
+ * Why this exists: after a logout on Tab A, Tab B still holds an
+ * in-memory `CryptoKey` handle to the (now-cleared) DPoP keypair
+ * and a session cookie whose server-side row was just revoked.
+ * Without a cross-tab signal, Tab B doesn't notice until its next
+ * network request — at which point the server 401s and the SPA
+ * bounces to `/login`. That's correctness-safe (see
+ * `docs/plan/dpop.md` Gate 8), but UX-poor: an idle Tab B silently
+ * pretends to be logged in for as long as it stays idle.
+ *
+ * This module fires a `BroadcastChannel` message so every other
+ * tab of the same origin can react synchronously — reset its
+ * session store, redirect to `/login`, no visible drift.
+ *
+ * Scope: session **invalidation** only. Not for cross-tab login
+ * (a fresh sign-in on Tab B while Tab A sits on `/login`); that's
+ * a general auth-store consistency concern, not DPoP-specific,
+ * and can be layered on later using the same primitive if needed.
+ *
+ * Fail-open contract mirrors the rest of the DPoP stack: if
+ * `BroadcastChannel` is unavailable (very old Safari, restricted
+ * webviews), broadcast/subscribe are no-ops. Users lose the
+ * instant-redirect UX; the natural 401-on-next-request path
+ * kicks in as before.
+ */
+
+const CHANNEL_NAME = 'oxicloud-session-cleared';
+
+/**
+ * Post a "session cleared" event to every other tab of this
+ * origin. The current tab does NOT receive its own message —
+ * `BroadcastChannel` skips the sender by design.
+ *
+ * Called from `logout()` after the server round trip completes
+ * (success or failure — user intent is what matters). Non-fatal
+ * on failure so the logout flow always finishes.
+ */
+export function broadcastSessionCleared(): void {
+	try {
+		const ch = new BroadcastChannel(CHANNEL_NAME);
+		ch.postMessage({ kind: 'session_cleared', at: Date.now() });
+		ch.close();
+	} catch (err) {
+		console.debug('session-broadcast: postMessage failed', err);
+	}
+}
+
+/**
+ * Subscribe to cross-tab session-cleared events. Wire this once
+ * from the root layout's `onMount`; the callback should reset
+ * the SPA's session store and navigate to `/login`.
+ *
+ * Returns a cleanup function that closes the channel — call it
+ * from the layout's `onDestroy` so hot-reload during dev doesn't
+ * leak listeners.
+ *
+ * Errors during subscription are swallowed to a no-op: same
+ * degradation posture as the rest of the DPoP stack.
+ */
+export function onSessionCleared(callback: () => void): () => void {
+	try {
+		const ch = new BroadcastChannel(CHANNEL_NAME);
+		ch.onmessage = () => {
+			try {
+				callback();
+			} catch (err) {
+				console.debug('session-broadcast: callback threw', err);
+			}
+		};
+		return () => ch.close();
+	} catch (err) {
+		console.debug('session-broadcast: subscribe failed', err);
+		return () => {};
+	}
+}

frontend/src/routes/+layout.svelte

@@ -9,6 +9,7 @@
 	import DialogHost from '$lib/components/DialogHost.svelte';
 	import Toaster from '$lib/components/Toaster.svelte';
 	import { setPasswordChangeRequiredHandler } from '$lib/api/client';
+	import { onSessionCleared } from '$lib/auth/session-broadcast';
 	import { session } from '$lib/stores/session.svelte';
 	import { ui } from '$lib/stores/ui.svelte';
 	import { hashUrlToPath } from '$lib/utils/hashRedirect';
@@ -61,6 +62,24 @@
 	});
 
 	onMount(async () => {
+		// Cross-tab logout — when ANOTHER tab logs out, wipe our
+		// session store and bounce to /login synchronously. Without
+		// this the natural 401-on-next-request path still catches
+		// it, just with visible delay for an idle tab. See
+		// `docs/plan/dpop.md` Gate 8.
+		//
+		// The cleanup closure returned by `onSessionCleared` is
+		// intentionally not wired to `onDestroy` — the root layout
+		// only unmounts on hot-reload, and a leaked BroadcastChannel
+		// there is far cheaper than the risk of missing an
+		// invalidation event during teardown.
+		onSessionCleared(() => {
+			session.reset();
+			// `replaceState: true` so the back button doesn't return
+			// the user to the now-dead protected page they were on.
+			void goto(resolve('/login'), { replaceState: true });
+		});
+
 		await killLegacyServiceWorker();
 
 		// The instant HTML boot splash has done its job — the app is mounted, so

frontend/vitest-setup.ts

@@ -54,3 +54,149 @@ for (const name of ['localStorage', 'sessionStorage']) {
 		g[name] = new MemoryStorage() as unknown as Storage;
 	}
 }
+
+// jsdom has no IndexedDB. `$lib/auth/dpop` uses it as a single-entry
+// key/value store for the browser DPoP keypair; without a working
+// backing store every test that touches login / fetch prints a
+// fail-open `console.debug` on stdout. Rather than pull in
+// `fake-indexeddb` for one call-site, provide a minimal in-memory
+// shim that covers exactly the API surface `dpop.ts` uses:
+//
+//   indexedDB.open(name)                        → IDBOpenDBRequest
+//     .onupgradeneeded / .onsuccess / .onerror  → callback slots
+//     .result → { objectStoreNames.contains,
+//                 createObjectStore, transaction, close }
+//   store.get(key)  / .put(value, key)  / .delete(key)
+//   tx.oncomplete / .onerror
+//
+// Tests that WANT to exercise DPoP semantics still mock the module
+// (see `src/lib/auth/dpop-proof.test.ts`). This shim is for the
+// login-path traversals that were noisy without it.
+if (!g.indexedDB) {
+	type Store = Map<string, unknown>;
+	type Db = {
+		stores: Map<string, Store>;
+		objectStoreNames: { contains: (n: string) => boolean };
+		createObjectStore: (n: string) => void;
+		transaction: (n: string, mode: 'readonly' | 'readwrite') => FakeTx;
+		close: () => void;
+	};
+	type FakeReq<T> = {
+		result: T | undefined;
+		error: unknown;
+		onsuccess: ((this: unknown, ev: Event) => void) | null;
+		onerror: ((this: unknown, ev: Event) => void) | null;
+	};
+	type FakeTx = {
+		objectStore: (n: string) => FakeStore;
+		oncomplete: ((this: unknown, ev: Event) => void) | null;
+		onerror: ((this: unknown, ev: Event) => void) | null;
+		_done: () => void;
+	};
+	type FakeStore = {
+		get: (key: string) => FakeReq<unknown>;
+		put: (value: unknown, key: string) => FakeReq<void>;
+		delete: (key: string) => FakeReq<void>;
+	};
+
+	// Per-database persistence: opening the same name again gives you
+	// back your previously-created stores + entries, so the module's
+	// "read a value someone else wrote" flow works across
+	// open→close→open cycles within one test.
+	const databases = new Map<string, Map<string, Store>>();
+
+	function makeStore(map: Store, tx: FakeTx): FakeStore {
+		const microDone = () => queueMicrotask(() => tx._done());
+		return {
+			get(key: string): FakeReq<unknown> {
+				const req: FakeReq<unknown> = {
+					result: map.get(key),
+					error: undefined,
+					onsuccess: null,
+					onerror: null
+				};
+				queueMicrotask(() => req.onsuccess?.call(req, new Event('success')));
+				microDone();
+				return req;
+			},
+			put(value: unknown, key: string): FakeReq<void> {
+				map.set(key, value);
+				const req: FakeReq<void> = {
+					result: undefined,
+					error: undefined,
+					onsuccess: null,
+					onerror: null
+				};
+				queueMicrotask(() => req.onsuccess?.call(req, new Event('success')));
+				microDone();
+				return req;
+			},
+			delete(key: string): FakeReq<void> {
+				map.delete(key);
+				const req: FakeReq<void> = {
+					result: undefined,
+					error: undefined,
+					onsuccess: null,
+					onerror: null
+				};
+				queueMicrotask(() => req.onsuccess?.call(req, new Event('success')));
+				microDone();
+				return req;
+			}
+		};
+	}
+
+	function makeDb(name: string): Db {
+		let stores = databases.get(name);
+		if (!stores) {
+			stores = new Map();
+			databases.set(name, stores);
+		}
+		return {
+			stores,
+			objectStoreNames: { contains: (n: string) => stores!.has(n) },
+			createObjectStore(n: string): void {
+				if (!stores!.has(n)) stores!.set(n, new Map());
+			},
+			transaction(n: string, _mode: 'readonly' | 'readwrite'): FakeTx {
+				const store = stores!.get(n);
+				if (!store) throw new Error(`fake-idb: store '${n}' not found`);
+				const tx: FakeTx = {
+					objectStore: () => makeStore(store, tx),
+					oncomplete: null,
+					onerror: null,
+					_done: () => tx.oncomplete?.call(tx, new Event('complete'))
+				};
+				return tx;
+			},
+			close(): void {
+				/* no-op — databases map keeps state across close */
+			}
+		};
+	}
+
+	g.indexedDB = {
+		open(name: string) {
+			const req: FakeReq<Db> & {
+				onupgradeneeded: ((this: unknown, ev: Event) => void) | null;
+			} = {
+				result: undefined,
+				error: undefined,
+				onsuccess: null,
+				onerror: null,
+				onupgradeneeded: null
+			};
+			queueMicrotask(() => {
+				const db = makeDb(name);
+				req.result = db;
+				// Fire upgradeneeded on FIRST open per database, so the
+				// module can call createObjectStore('keypair') exactly
+				// like the real API expects.
+				const stores = databases.get(name)!;
+				if (stores.size === 0) req.onupgradeneeded?.call(req, new Event('upgradeneeded'));
+				req.onsuccess?.call(req, new Event('success'));
+			});
+			return req;
+		}
+	};
+}