UME: renew token when expires_in is 0; token UI loading + toasts; sync thread status hint

- keepalive: call renew when has_token and (expires_in<=0 or below renew_before) so 0s stuck state self-heals\n- alarms/inventory auto loops: set last_error while pulling so table is not stuck at init with no hint\n- UmePage: warn pills for connected+需续期, spinners on token actions, toast ok/err from App, invalidate sync status after token ops

Co-authored-by: Cursor <cursoragent@cursor.com>

web/src/types.ts

@@ -148,12 +148,13 @@ export type UmeAlarmItem = {
 };
 
 export type UmeTokenStatus = {
-  ok: boolean;
+  ok?: boolean;
   has_token: boolean;
   expires_in_s: number;
   expires_at_epoch_s: number;
   auth_header: string;
   token_preview?: string;
+  changed?: boolean;
   error_kind?: string;
   error?: string;
 };