fix(settings): a tab-return read never undoes a pick or save made while it was out

- session-ui.js: drop the answer when the case-sync chain moved during the read; settings-ui.js calls _applyServerCaseSettings with ?.
- i18n.js: zh-CN for the failed case-options save toast, case name passed through
- tests: regression for the stale read, zh-CN toast row

src/web/public/i18n.js

@@ -1734,6 +1734,11 @@
         (_m, what, why) =>
           `${what === 'Run mode' ? '运行模式' : '重生预设'}已保存到本设备，但未保存到服务器：${ZH_CN[why] || why}`,
       ],
+      // The case-options save (session-ui.js _pushCaseSettings): the case name passes through.
+      [
+        /^Options for "([^"]+)" \(until the next sync\) saved on this device, not on the server: ([\s\S]+)$/,
+        (_m, name, why) => `案例“${name}”的选项已保存到本设备（同步前有效），但未保存到服务器：${ZH_CN[why] || why}`,
+      ],
       // A dialog read off a hook-less CLI's screen (src/web/screen-blocked.ts), as the
       // notification drawer shows it. The CLI's label passes through.
       [/^(.+) is waiting for your answer in the terminal$/, (_m, cli) => `${cli} 正在终端中等待你的回答`],

src/web/public/session-ui.js

@@ -3775,11 +3775,13 @@ Object.assign(CodemanApp.prototype, {
     if (this.loadAppSettingsFromStorage?.()?.syncCaseState !== true) return;
     const seq = (this._caseSyncRefresh = (this._caseSyncRefresh || 0) + 1);
     try {
-      await this._caseSyncChain; // this device's own saves land first, so the copy read next includes them
+      const chain = this._caseSyncChain;
+      await chain; // this device's own saves land first, so the copy read next includes them
       const res = await fetch('/api/settings');
       if (!res.ok) return;
       const server = (await res.json())?.data ?? null;
       if (seq !== this._caseSyncRefresh || !server) return; // a newer refresh owns the answer
+      if (this._caseSyncChain !== chain) return; // a save or pick made while the read was out is newer than it
       this._adoptServerCaseSyncPreference(server);
       if (server.syncCaseState !== true) return;
       this._applyServerCaseSettings(server);

src/web/public/settings-ui.js

@@ -5282,7 +5282,7 @@ Object.assign(CodemanApp.prototype, {
         // installs that had saved `false` (agent-skill-default-migration.ts).
         if (!('agentSkillEnabled' in appSettings)) delete merged.agentSkillEnabled;
         this.saveAppSettingsToStorage(merged);
-        this._applyServerCaseSettings(settings);
+        this._applyServerCaseSettings?.(settings);
 
         // Apply notification prefs from server if present (only if localStorage has none)
         if (notificationPreferences && this.notificationManager) {