Fix TTS server status errors and startup warnings

- Fixed 'app is not defined' errors by using current_app
- Improved TTS health check to handle missing /health endpoint
- Fixed database trigger creation to be idempotent
- Added .env.example with all configuration options
- Updated README with security configuration instructions

migrations/add_user_authentication.py

@@ -178,6 +178,11 @@ def upgrade():
         $$ language 'plpgsql';
     """)
     
+    # Drop existing trigger if it exists and recreate it
+    op.execute("""
+        DROP TRIGGER IF EXISTS update_users_updated_at ON users;
+    """)
+    
     # Create trigger for users table
     op.execute("""
         CREATE TRIGGER update_users_updated_at