fix: 修复集成测试中发现的两个 bug

1. saveToDisk 过滤 bug：新创建的空会话（无 sessionId）被持久化过滤器
   跳过，导致 /reset 后重启服务会丢失新会话。改为保存 group 内所有
   session。

2. /switch 未释放 persistent executor：切换会话时旧的长驻 Claude 进程
   仍在运行，其 sessionId 会覆盖切换后的会话。现在 /switch 和
   /session 命令都会调用 releaseExecutor。

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: hahhforest

src/bridge/command-handler.ts

@@ -459,6 +459,9 @@ export class CommandHandler {
     }
     const success = this.sessionManager.switchSession(chatId, num - 1);
     if (success) {
+      // Release persistent executor so the next message picks up the
+      // switched session's sessionId instead of the old process's.
+      try { await this.releaseExecutor(chatId, 'session-switch'); } catch {}
       const session = this.sessionManager.getSession(chatId);
       const sid = session.sessionId ? `\`${session.sessionId.slice(0, 8)}...\`` : '_new_';
       await this.sender.sendTextNotice(chatId, '✅ Switched', `Switched to session ${num} (${sid}).`, 'green');
@@ -477,6 +480,7 @@ export class CommandHandler {
     }
     const idx = this.sessionManager.switchToSessionByPrefix(chatId, prefix);
     if (idx >= 0) {
+      try { await this.releaseExecutor(chatId, 'session-switch'); } catch {}
       const session = this.sessionManager.getSession(chatId);
       const sid = session.sessionId ? `\`${session.sessionId.slice(0, 8)}...\`` : '_new_';
       await this.sender.sendTextNotice(chatId, '✅ Switched',

src/engines/claude/session-manager.ts

@@ -331,18 +331,16 @@ export class SessionManager {
     try {
       const data: Record<string, PersistedSessionGroup> = {};
       for (const [chatId, group] of this.groups) {
-        const persistedSessions = group.sessions
-          .filter(s => s.sessionId || s.model || s.engine || s.activeGoal || s.title)
-          .map(s => this.sessionToPersisted(s));
-        if (persistedSessions.length > 0) {
-          // Recalculate activeIndex after filtering
-          const activeSession = group.sessions[group.activeIndex];
-          const newActiveIndex = persistedSessions.findIndex(
-            ps => ps.sessionId === (activeSession.sessionId || '') && ps.lastUsed === activeSession.lastUsed,
-          );
+        // Persist all sessions in a group — even new ones without a sessionId yet.
+        // The group is the unit of persistence; filtering individual sessions
+        // would lose newly-created (post-/reset) sessions before their first turn.
+        const hasContent = group.sessions.some(
+          s => s.sessionId || s.model || s.engine || s.activeGoal || s.title,
+        );
+        if (hasContent || group.sessions.length > 1) {
           data[chatId] = {
-            activeIndex: Math.max(0, newActiveIndex),
-            sessions: persistedSessions,
+            activeIndex: group.activeIndex,
+            sessions: group.sessions.map(s => this.sessionToPersisted(s)),
           };
         }
       }