Blur gallery images by default, sync progress UI, and add chat/monitor tests

- Blur NSFW media gallery images until hover/reveal
- Surface chat sync progress in the dashboard header
- Extend chat service, cache, and monitor with delta-media handling
- Add tests for chat cooldown, delta media, and monitor flows

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

tests/chat-service-cooldown.test.ts

@@ -1,5 +1,9 @@
 import { describe, it, expect } from 'vitest';
+import fs from 'fs/promises';
+import path from 'path';
+import os from 'os';
 import { ChatService } from '../src/services/chat/service.js';
+import { ChatCache } from '../src/services/chat/cache.js';
 import { MatrixClient, MatrixRateLimitError } from '../src/services/chat/matrix/client.js';
 import { createMockLogger } from './mockLogger.js';
 
@@ -80,6 +84,82 @@ describe('ChatService invitation cooldown', () => {
     expect(result).toBe(false);
   });
 
+  it('persists the cooldown to disk and restores it after a fresh service load', async () => {
+    const logger = createMockLogger();
+    const tmpDir = await fs.mkdtemp(path.join(os.tmpdir(), 'chat-cooldown-'));
+    const cacheFile = path.join(tmpDir, 'chat-cache.json');
+    try {
+      const matrix = new MatrixClient(creds, logger, { minRequestIntervalMs: 0 });
+      const cache1 = new ChatCache(logger, cacheFile);
+      const svc1 = new ChatService(matrix, logger, undefined, undefined, undefined, undefined, cache1);
+      svc1.setInvitationCooldown(
+        new MatrixRateLimitError('429', 120_000, 'M_LIMIT_EXCEEDED', null),
+      );
+      // setInvitationCooldown kicks off an async save; flush the queue.
+      await cache1.save();
+
+      const cache2 = new ChatCache(logger, cacheFile);
+      const svc2 = new ChatService(matrix, logger, undefined, undefined, undefined, undefined, cache2);
+      await svc2.loadCache();
+      const restored = svc2.getInvitationCooldown();
+      expect(restored).not.toBeNull();
+      expect(restored!.until).toBeGreaterThan(Date.now() + 100_000);
+    } finally {
+      await fs.rm(tmpDir, { recursive: true, force: true });
+    }
+  });
+
+  it('preserves on-disk chats and lastFullSyncAt when a cooldown fires before loadCache', async () => {
+    const logger = createMockLogger();
+    const tmpDir = await fs.mkdtemp(path.join(os.tmpdir(), 'chat-cooldown-preserve-'));
+    const cacheFile = path.join(tmpDir, 'chat-cache.json');
+    try {
+      // Pre-seed an existing cache with a completed full sync and known chats.
+      const existing = {
+        version: 1,
+        savedAt: Date.now() - 60_000,
+        chats: [
+          {
+            username: 'alice',
+            roomName: 'alice',
+            lastMessageTime: Date.now() - 30_000,
+            lastMessageSnippet: 'hi',
+            isFromUs: false,
+            unread: false,
+            roomId: '!room:example.test',
+          },
+        ],
+        nextBatch: 's42_1',
+        lastFullSyncAt: Date.now() - 120_000,
+        lastDeltaSyncAt: Date.now() - 30_000,
+        cooldown: null,
+      };
+      await fs.writeFile(cacheFile, JSON.stringify(existing), 'utf-8');
+
+      const matrix = new MatrixClient(creds, logger, { minRequestIntervalMs: 0 });
+      const cache = new ChatCache(logger, cacheFile);
+      const svc = new ChatService(matrix, logger, undefined, undefined, undefined, undefined, cache);
+
+      // Cooldown fires before loadCache() — the in-memory chats are still [].
+      svc.setInvitationCooldown(
+        new MatrixRateLimitError('429', 60_000, 'M_LIMIT_EXCEEDED', null),
+      );
+      // Flush the async persist (read + write).
+      await cache.persistCooldown();
+
+      const raw = await fs.readFile(cacheFile, 'utf-8');
+      const after = JSON.parse(raw);
+      expect(after.chats).toHaveLength(1);
+      expect(after.chats[0].username).toBe('alice');
+      expect(after.lastFullSyncAt).toBe(existing.lastFullSyncAt);
+      expect(after.nextBatch).toBe('s42_1');
+      expect(after.cooldown).not.toBeNull();
+      expect(after.cooldown.reason).toMatch(/M_LIMIT_EXCEEDED/);
+    } finally {
+      await fs.rm(tmpDir, { recursive: true, force: true });
+    }
+  });
+
   it('sendChatMessage records a cooldown when the homeserver rate-limits a reply', async () => {
     const logger = createMockLogger();
     const matrix = new MatrixClient(creds, logger, { minRequestIntervalMs: 0 });