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/testUtils.ts

@@ -34,6 +34,9 @@ export function getTestConfig(overrides?: Partial<Config>): Config {
       targetGenders: ['female'],
       filterSellers: true,
       sellerKeywords: ['onlyfans', 'fansly'],
+      sellerDomains: [],
+      prioritizeRecentPosts: false,
+      recentWindowMinutes: 60,
       ...overrides?.reddit,
     },
     openrouter: {