fix(server-storage): offline recheck checks only the instance; sign-out always navigates

The recheck on going offline ran a full refresh: when /instance answered
but /user-state kept failing, each failed read set the page offline
again and started the next one at once, bypassing the retry interval.
It now checks the instance only; reads wait for the retry.

Sign-out navigates to sign-in itself, also when the page is signed out
already: a guard (unsaved Settings) may have cancelled the redirect the
first time, and the state change that drives it does not repeat.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/architecture/pwa-self-hosted.md

@@ -336,7 +336,10 @@ settings and guards read them in every build.
   before sign-in sends the token. So does a page that went offline before
   its next read: until then it sends neither the token nor writes (a
   replaced volume at the same address is another database), and it checks
-  as soon as it goes offline, so a blip costs no retry interval. Both turn
+  the instance as soon as it goes offline, so a blip costs no retry
+  interval (only the instance: a read that keeps failing waits for the
+  retry). Sign-out always navigates to sign-in, also when a guard kept the
+  page the first time. Both turn
   the guard's 401 (`isServerAccessChallenge`) into `reportAccessDenied()`,
   as the storage API client does with any 401, so a token changed on the
   server sends an open page back to sign-in; a late 401 for a token

libs/services/src/lib/server-storage/server-storage-session.spec.ts

@@ -1,6 +1,6 @@
 import { TestBed } from '@angular/core/testing';
 import { MatSnackBar } from '@angular/material/snack-bar';
-import { provideRouter } from '@angular/router';
+import { provideRouter, Router } from '@angular/router';
 import { TranslateService } from '@ngx-translate/core';
 import { PlaylistStorageBackend } from '../playlist-storage-backend';
 import { RuntimeCapabilitiesService } from '../runtime-capabilities.service';
@@ -187,6 +187,21 @@ describe('ServerStorageSession', () => {
         delete (document as { visibilityState?: unknown }).visibilityState;
     });
 
+    it('goes to sign-in on every sign-out, also when already signed out', async () => {
+        const { session } = setup('none');
+        await session.start();
+        const navigate = jest
+            .spyOn(TestBed.inject(Router), 'navigateByUrl')
+            .mockResolvedValue(false);
+
+        session.signOut();
+        // A guard kept the page (unsaved Settings); the user signs out again.
+        session.signOut();
+
+        expect(navigate).toHaveBeenCalledTimes(2);
+        expect(navigate).toHaveBeenLastCalledWith('/server-sign-in');
+    });
+
     describe('after losing the server', () => {
         const answer = (body: unknown) => ({
             status: 200,
@@ -226,6 +241,30 @@ describe('ServerStorageSession', () => {
             );
         });
 
+        it('checks only the instance at once when it goes offline', async () => {
+            const { session, status } = setup('none');
+            await session.start();
+            // The instance answers, its user data does not.
+            fetchMock.mockImplementation(async (url: string) =>
+                url.endsWith('/instance')
+                    ? answer({ instanceId: 'i-1' })
+                    : { status: 503, ok: false, headers: new Headers() }
+            );
+            fetchMock.mockClear();
+
+            status.reportOffline();
+            TestBed.tick();
+            for (let turn = 0; turn < 10; turn += 1) {
+                await Promise.resolve();
+            }
+
+            expect(status.isVerified()).toBe(true);
+            // A failing read waits for the retry interval, not a loop.
+            expect(fetchMock.mock.calls.map(([url]) => url)).toEqual([
+                '/api/v1/instance',
+            ]);
+        });
+
         it('reloads when another instance answers at the address', async () => {
             const { session, status } = setup('none');
             const reload = jest

libs/services/src/lib/server-storage/server-storage-session.ts

@@ -74,8 +74,14 @@ export class ServerStorageSession {
         effect(() => {
             // Gone offline, the token and writes wait for the instance
             // check: after a blip it passes at once, not at the next retry.
-            if (this.status.state() === 'offline') {
-                untracked(() => void this.refresh());
+            // Only the check: a read failing on its own waits for the retry.
+            if (
+                this.status.state() === 'offline' &&
+                !this.config.startedOffline
+            ) {
+                untracked(
+                    () => void this.ensureVerified().catch(() => undefined)
+                );
             }
         });
     }
@@ -164,6 +170,9 @@ export class ServerStorageSession {
     signOut(): void {
         clearServerAccessToken();
         this.status.reportUnauthorized();
+        // Also when signed out already: a guard (unsaved Settings) may have
+        // kept the page here the first time.
+        void this.router.navigateByUrl(SERVER_SIGN_IN_PATH);
     }
 
     private listen(): void {