fix save indicator timing and auto-save history loss on resume

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/servers/api/saved-sessions/saved-sessions.ts

@@ -93,20 +93,30 @@ savedSessionsRouter.put('/:id', async (ctx) => {
 
   const homeDir = getHomeDirForRole(user.email, user.role);
 
+  // Load existing saved session to get previous messages
+  const existing = await getSavedSession(id, user.id);
+  if (!existing) {
+    return ctx.json({ error: 'Not found' }, 404);
+  }
+
   let meta;
-  let messages: Message[];
+  let newMessages: Message[];
   try {
     const loaded = await storage.loadSession(homeDir, sessionId);
     meta = loaded.meta;
-    messages = loaded.messages;
+    newMessages = loaded.messages;
   } catch {
     return ctx.json({ error: 'Session not found on disk' }, 404);
   }
 
+  // Merge: old DB messages (from before resume) + new disk messages (from this session)
+  const oldMessages = (existing.rawMessages ?? []) as Message[];
+  const mergedMessages = [...oldMessages, ...newMessages];
+
   const updated = await updateSavedSessionMessages(
     id,
     user.id,
-    messages,
+    mergedMessages,
     meta.cost as unknown as Record<string, unknown>,
   );