UX/UI/perf pass: admin tabs, theme toggle, log polish, mod search, JAR cache

- Admin page split into tabs (Server/Players/Chat/Mods/Backups/Logs) with
  hash + localStorage persistence; inactive tabs no longer mount.
- Log viewer: level color-coding, search, level filter chips, auto-scroll
  toggle, copy button, visible-line count.
- Installed mods list: search field + side filter (all/both/server/client)
  with live count; public ModList gets skeleton + empty states and search.
- Theme toggle with no-flash inline init, localStorage + system preference.
- Layout: full OG / Twitter metadata, title template, keywords,
  dual-theme themeColor, metadataBase.
- lib/mods.ts: per-jar mtime+size parse cache (cold 6s -> warm ~45ms on
  /api/mods for the full mod list); cache eviction on mod removal.
- ChatBridge polling eased 3s -> 5s with 2s stale window.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

components/ChatBridge.tsx

@@ -29,7 +29,8 @@ export function ChatBridge() {
   const { data: messages = [] } = useQuery<ChatMessage[]>({
     queryKey: ["chat"],
     queryFn: () => fetch("/api/chat?lines=50").then((r) => r.json()),
-    refetchInterval: 3000,
+    refetchInterval: 5000,
+    staleTime: 2000,
   });
 
   const send = useMutation({