fix(usage): reject transient transport failures so retry and keep-last-good work

Usage/quota queries frequently showed spurious "query failed" states that
manual refresh could not clear (#3820). Root cause: all transport-level
failures were folded into Ok(success:false), so react-query's retry never
fired and the failure body poisoned the cache as regular data.

Backend:
- balance/coding_plan/subscription services now return Err for send
  failures and body-read failures (read body via bytes() before
  serde_json::from_slice; reqwest's json() wraps read errors as Decode,
  making error-kind checks on it dead code). Auth/4xx/parse errors stay
  Ok(success:false) and surface immediately.
- Script path maps transient AppError keys (request_failed /
  read_response_failed) to Err; Volcengine adds a Transient call variant.
- Command layer skips snapshot persistence, usage-cache-updated emit and
  tray refresh on Err so the cache bridge cannot overwrite retained data.
- Expired-credential retry propagates transient errors instead of
  rewriting them as "OAuth token has expired".

Frontend:
- resolveDisplayUsage generalized to subscription quotas; 5th param is now
  an options object with a `rejected` flag: stale success data retained by
  react-query across rejections is re-anchored to dataUpdatedAt and expires
  through the same 10-minute keep-last-good window instead of being shown
  indefinitely (a total outage used to mask longer than a single 5xx).
- useSubscriptionQuota / useCodexOauthQuota gain keep-last-good with
  per-scope snapshot reset; rejected queries with no displayable value
  synthesize a failure placeholder carrying the real error message so
  footers keep rendering a retry entry point.
- HTTP 429 is classified transient (retry-later) alongside 5xx.
- UsageScriptModal surfaces string rejections via extractErrorMessage.

Tests: 6 backend behavior tests drive real HTTP against a local listener
to pin the Err/Ok channel semantics; frontend suite extends
keepLastGoodUsage coverage (405 passing).

src-tauri/src/commands/codex_oauth.rs

@@ -49,13 +49,14 @@ pub async fn get_codex_oauth_quota(
         }
     };
 
-    Ok(query_codex_quota(
+    // 瞬时传输失败以 Err 传播（前端 reject → retry + 保留上次成功值）。
+    query_codex_quota(
         &token,
         Some(&id),
         "codex_oauth",
         "Codex OAuth access token expired or rejected. Please re-login via cc-switch.",
     )
-    .await)
+    .await
 }
 
 /// 获取 Codex OAuth (ChatGPT Plus/Pro) 可用模型列表

src-tauri/src/commands/provider.rs

@@ -381,32 +381,30 @@ pub async fn queryProviderUsage(
 ) -> Result<crate::provider::UsageResult, String> {
     let app_type = AppType::from_str(&app).map_err(|e| e.to_string())?;
     // inner 可能以两种形式失败：
-    //   1) 返回 Ok(UsageResult { success: false, .. }) —— 业务失败（401、脚本报错等）
-    //   2) 返回 Err(String) —— RPC/DB/Copilot fetch_usage 等 transport 层失败
-    // 两种都要把"失败"写进 UsageCache 并刷新托盘，让 format_script_summary 的
-    // success 守卫生效、suffix 自然消失，避免旧 success 快照长期滞留。
-    // 同时保持原始 Err 返回给前端 React Query 的 onError 回调，不吞错误。
+    //   1) 返回 Ok(UsageResult { success: false, .. }) —— 确定性失败（401、脚本
+    //      报错、未知供应商等）。写进 UsageCache 并刷新托盘，让
+    //      format_script_summary 的 success 守卫生效、suffix 自然消失。
+    //   2) 返回 Err(String) —— 瞬时传输失败（网络/超时）及 DB/Copilot fetch 等。
+    //      不写失败快照、不 emit：保留上一份托盘快照，与前端 react-query reject
+    //      保留上次 data 的语义一致；否则失败快照会经 useUsageCacheBridge 盲写
+    //      回 query 缓存，抹掉 reject 本该保留的旧值。
     let inner =
         query_provider_usage_inner(&state, &copilot_state, app_type.clone(), &providerId).await;
-    let snapshot = match &inner {
-        Ok(r) => r.clone(),
-        Err(err_msg) => crate::provider::UsageResult {
-            success: false,
-            data: None,
-            error: Some(err_msg.clone()),
-        },
-    };
-    let payload = serde_json::json!({
-        "kind": "script",
-        "appType": app_type.as_str(),
-        "providerId": &providerId,
-        "data": &snapshot,
-    });
-    if let Err(e) = app_handle.emit("usage-cache-updated", payload) {
-        log::error!("emit usage-cache-updated (script) 失败: {e}");
+    if let Ok(snapshot) = &inner {
+        let payload = serde_json::json!({
+            "kind": "script",
+            "appType": app_type.as_str(),
+            "providerId": &providerId,
+            "data": snapshot,
+        });
+        if let Err(e) = app_handle.emit("usage-cache-updated", payload) {
+            log::error!("emit usage-cache-updated (script) 失败: {e}");
+        }
+        state
+            .usage_cache
+            .put_script(app_type, providerId, snapshot.clone());
+        crate::tray::schedule_tray_refresh(&app_handle);
     }
-    state.usage_cache.put_script(app_type, providerId, snapshot);
-    crate::tray::schedule_tray_refresh(&app_handle);
     inner
 }
 

src-tauri/src/commands/subscription.rs

@@ -2,17 +2,19 @@ use std::str::FromStr;
 use tauri::{Emitter, State};
 
 use crate::app_config::AppType;
-use crate::services::subscription::{CredentialStatus, SubscriptionQuota};
+use crate::services::subscription::SubscriptionQuota;
 use crate::store::AppState;
 
 /// 查询官方订阅额度
 ///
 /// 读取 CLI 工具已有的 OAuth 凭据并调用官方 API 获取使用额度。
-/// 结果（无论业务失败还是 transport 层 Err）都会写入 `UsageCache`、通知托盘
-/// 刷新，并 emit `usage-cache-updated`，让前端 React Query 与托盘共享同一份
-/// 最新数据。失败快照写入后 `format_subscription_summary` 会通过 `success=false`
-/// 守卫返回 `None`，托盘 suffix 自然消失，避免长期滞留旧配额数字。
-/// Err 原样向前端返回，React Query 的 onError 不会被吞掉。
+/// `Ok`（成功或确定性失败）写入 `UsageCache`、通知托盘刷新并 emit
+/// `usage-cache-updated`，让前端 React Query 与托盘共享同一份最新数据；失败
+/// 快照写入后 `format_subscription_summary` 会通过 `success=false` 守卫返回
+/// `None`，托盘 suffix 自然消失，避免长期滞留旧配额数字。
+/// `Err`（瞬时传输失败）不写快照、不 emit：保留上一份托盘快照，与前端
+/// react-query reject 保留上次 data 的语义一致（emit 失败快照会经
+/// `useUsageCacheBridge` 盲写回 query 缓存，抹掉本该保留的旧值）。
 #[tauri::command]
 pub async fn get_subscription_quota(
     app: tauri::AppHandle,
@@ -20,22 +22,21 @@ pub async fn get_subscription_quota(
     tool: String,
 ) -> Result<SubscriptionQuota, String> {
     let inner = crate::services::subscription::get_subscription_quota(&tool).await;
-    let snapshot = match &inner {
-        Ok(q) => q.clone(),
-        // transport 层 Err —— 凭据状态不明，用 Valid 表达"凭据没问题，是通信/parse 出错"。
-        Err(err_msg) => SubscriptionQuota::error(&tool, CredentialStatus::Valid, err_msg.clone()),
-    };
-    if let Ok(app_type) = AppType::from_str(&tool) {
-        let payload = serde_json::json!({
-            "kind": "subscription",
-            "appType": app_type.as_str(),
-            "data": &snapshot,
-        });
-        if let Err(e) = app.emit("usage-cache-updated", payload) {
-            log::error!("emit usage-cache-updated (subscription) 失败: {e}");
+    if let Ok(snapshot) = &inner {
+        if let Ok(app_type) = AppType::from_str(&tool) {
+            let payload = serde_json::json!({
+                "kind": "subscription",
+                "appType": app_type.as_str(),
+                "data": snapshot,
+            });
+            if let Err(e) = app.emit("usage-cache-updated", payload) {
+                log::error!("emit usage-cache-updated (subscription) 失败: {e}");
+            }
+            state
+                .usage_cache
+                .put_subscription(app_type, snapshot.clone());
+            crate::tray::schedule_tray_refresh(&app);
         }
-        state.usage_cache.put_subscription(app_type, snapshot);
-        crate::tray::schedule_tray_refresh(&app);
     }
     inner
 }