fix(2meet-data-optimizer): keep the audit trail of mode changes and snapshot deletions

- TMDO_Logger::notice() is always written to the error log (it had no
  callers); bridge_mode_changed and snapshot_deleted use it. Since PR-095
  info() is silent without WP_DEBUG_LOG, which left no record of who switched
  a mode or deleted a snapshot (security review L1)
- Verify: LoggerTest (notice always logged, info gated), unit 703,
  integration 585, phpcs, stan
- PR: PR-113 (2.3 acceptance security review)

includes/class-tmdo-logger.php

@@ -77,15 +77,16 @@ class TMDO_Logger {
 	}
 
 	/**
-	 * Log a NOTICE-level event — alias of info() for callers that want a stronger
-	 * level intent. Same routing (error_log only).
+	 * Log a NOTICE-level event: always written to the PHP error log (unlike
+	 * info()), for the audit trail of operator actions such as mode changes
+	 * and snapshot deletions.
 	 *
-	 * @param string $event   Event name.
-	 * @param array  $context Structured context.
+	 * @param string               $event   Event name.
+	 * @param array<string, mixed> $context Structured context.
 	 * @return void
 	 */
 	public static function notice( string $event, array $context = array() ): void {
-		self::info( $event, $context );
+		error_log( sprintf( '[WPDO][NOTICE][%s] %s', $event, $context ? wp_json_encode( $context, JSON_UNESCAPED_UNICODE ) : '' ) );
 	}
 
 	/**