feat(db): migrate from lowdb to SQLite with repos pattern

- Add modular DB layer (adapters, migrations, repos, helpers)
- Replace localDb/usageDb/requestDetailsDb monoliths with repos
- Add Tailscale tunnel integration & status check API
- Add /api/cli-tools/all-statuses aggregated endpoint
- Add settingsStore (Zustand) and mitm/dbReader
- Add DB unit tests (benchmark, concurrent, migration, vs-lowdb)

src/shared/components/RequestLogger.js

@@ -114,7 +114,7 @@ export default function RequestLogger() {
         </div>
       </Card>
       <div className="text-[10px] text-text-muted italic">
-        Logs are saved to log.txt in the application data directory.
+        Logs are loaded from the request history database.
       </div>
     </div>
   );