refactor: remove Review tab, make UI state client-side, fix Jakarta time in analytics

- Remove Review tab completely (was redundant with Messages flagged view)
- UI state now client-side only (localStorage) — no server API calls for tab/channel/guild selection
- Fixes dashboard crash when server is down — now loads fully client-side
- Live panel still uses server API for voice/media operations (only what needs it)
- Analytics hourly chart labels now show Jakarta time (WIB/UTC+7) instead of UTC
- Analytics formatTimeAgo uses Jakarta time reference
- Reduced tabs to 3: Live, Messages, Analytics
- Removed unused uiState API imports and server-side state fetching

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/components/layout/Header.tsx

@@ -8,14 +8,12 @@ const titles: Record<DashboardTab, string> = {
   live: "Voice, Media & Recordings",
   messages: "Messages & Moderation",
   analytics: "Analytics & Insights",
-  review: "Moderation Review",
 };
 
 const subtitles: Record<DashboardTab, string> = {
   live: "Join voice channels, play media, stream audio, and browse recordings.",
   messages: "Capture, analyse, and moderate Discord messages.",
   analytics: "Server moderation statistics and trends.",
-  review: "Review AI-flagged messages for moderation.",
 };
 
 interface HeaderProps {