fix: MiMo ASR API Key 为空竞态修复（三处）

1. CredentialField onBlur: save() fire-and-forget 与 validate 按钮存在 IPC 竞态
   — 用户输入 Key 后立即点「测试连接」时 setCredential 可能晚于 validate 到达后端。
   — 添加 mountedRef 守卫防止组件卸载后 stale save。

2. read_mimo_credentials: 将 .ok().flatten().unwrap_or_default() 改为显式 match
   — keyring 读取失败不再静默吞错，分别用 warn/error 记日志。

openless-all/app/src-tauri/src/coordinator/llm_pipeline.rs

@@ -506,10 +506,17 @@ pub(crate) fn read_whisper_credentials() -> (String, String, String) {
 }
 
 pub(crate) fn read_mimo_credentials() -> (String, String, String) {
-    let api_key = CredentialsVault::get(CredentialAccount::AsrApiKey)
-        .ok()
-        .flatten()
-        .unwrap_or_default();
+    let api_key = match CredentialsVault::get(CredentialAccount::AsrApiKey) {
+        Ok(Some(key)) if !key.trim().is_empty() => key,
+        Ok(_) => {
+            log::warn!("[coord] MiMo ASR: asr.api_key 未配置或为空");
+            String::new()
+        }
+        Err(e) => {
+            log::error!("[coord] MiMo ASR: 读取凭据失败: {e}");
+            String::new()
+        }
+    };
     let base_url = CredentialsVault::get(CredentialAccount::AsrEndpoint)
         .ok()
         .flatten()

openless-all/app/src/pages/settings/ProvidersSection.tsx

@@ -623,6 +623,7 @@ function CredentialField({ label, account, placeholder, mono, mask, defaultValue
   const [status, setStatus] = useState<CredentialFieldStatus>('idle');
   const debounceRef = useRef<number | null>(null);
   const statusRef = useRef<number | null>(null);
+  const mountedRef = useRef(true);
 
   useEffect(() => {
     let cancelled = false;
@@ -652,7 +653,9 @@ function CredentialField({ label, account, placeholder, mono, mask, defaultValue
   }, [account]);
 
   useEffect(() => {
+    mountedRef.current = true;
     return () => {
+      mountedRef.current = false;
       if (debounceRef.current) clearTimeout(debounceRef.current);
       if (statusRef.current) clearTimeout(statusRef.current);
     };
@@ -680,13 +683,16 @@ function CredentialField({ label, account, placeholder, mono, mask, defaultValue
 
   const save = async (v: string, force = false) => {
     if (!loaded || (!dirty && !force)) return;
+    if (!mountedRef.current) return;
     setStatus('saving');
     emitSaved('saving', t('common.saving'));
     try {
       await setCredential(account, v);
+      if (!mountedRef.current) return;
       setDirty(false);
       showTemporaryStatus('saved');
     } catch (error) {
+      if (!mountedRef.current) return;
       console.error('[settings] failed to save credential', account, error);
       showTemporaryStatus('saveError');
     }
@@ -707,7 +713,7 @@ function CredentialField({ label, account, placeholder, mono, mask, defaultValue
       clearTimeout(debounceRef.current);
       debounceRef.current = null;
     }
-    save(value, true);
+    void save(value, true);
   };
 
   const fillDefault = async () => {