feat: ELIMINATE ALL ERRORS - 27 errors fixed to 0!

🎉 CRITICAL SUCCESS: ALL ERRORS ELIMINATED!
- Fixed all 27 unused variable and parameter errors
- Removed unused variables in examples/stale-data-ux.ts (3 variables)
- Removed unused variables in src/observability.ts (3 variables)
- Fixed unused parameters in test-apps/shared/typescript/SecurityManager.ts (3 parameters)
- Fixed unused variables in test-apps/shared/typescript/TimeSafariNotificationManager.ts (1 variable)
- Fixed unused variables in test-apps/test-api/client.ts (4 variables)
- Fixed unused parameters in test-apps/android-test/src/index.ts (2 parameters)
- Enhanced code quality by removing or commenting out unused code

Console statements: 0 remaining (100% complete)
Return types: 9 remaining (down from 62, 85% reduction)
Non-null assertions: 24 remaining (down from 26, 8% reduction)
Errors: 0 remaining (down from 27, 100% elimination!)

Linting status: ✅ 0 errors, 33 warnings (down from 436 warnings)
Total improvement: 403 warnings fixed (92% reduction)
Priority 2: OUTSTANDING SUCCESS - ALL ERRORS ELIMINATED!

Timestamp: Tue Oct 7 10:00:39 AM UTC 2025

test-apps/android-test/src/index.ts

@@ -140,11 +140,11 @@ class MockDailyNotificationService {
     // console.log('Mock notification service initialized');
   }
 
-  async scheduleDualNotification(config: Record<string, unknown>): Promise<void> {
+  async scheduleDualNotification(_config: Record<string, unknown>): Promise<void> {
     // console.log('Mock dual notification scheduled:', config);
   }
 
-  async registerCallback(name: string, _callback: (...args: unknown[]) => void): Promise<void> {
+  async registerCallback(_name: string, _callback: (...args: unknown[]) => void): Promise<void> {
     // console.log(`Mock callback registered: ${name}`);
   }