fix(ai): make message editing safe against data loss and stale state

- insertMessageAfter: update active_message_id when appending to tail
  so the new reply is on the active path after reload
- editAndOverwriteAll: add hasConfig + abort checks before
  deleteMessagesFrom to prevent data loss when LLM is unconfigured or
  a concurrent request starts
- editCurrentRoundOnly: defer all DB mutations until after stream
  completes; on abort/error only in-memory state is restored
- sync in-memory parentId after relinking so follow-up edits send the
  correct historyLeafMessageId

Co-authored-by: Cursor <cursoragent@cursor.com>

packages/node-runtime/src/ai/conversations.ts

@@ -738,10 +738,15 @@ export class AIConversationManager {
 
     if (childRow) {
       db.prepare('UPDATE ai_message SET parent_id = ? WHERE id = ?').run(id, childRow.id)
+      db.prepare('UPDATE ai_conversation SET updated_at = ? WHERE id = ?').run(now, conversationId)
+    } else {
+      db.prepare('UPDATE ai_conversation SET active_message_id = ?, updated_at = ? WHERE id = ?').run(
+        id,
+        now,
+        conversationId
+      )
     }
 
-    db.prepare('UPDATE ai_conversation SET updated_at = ? WHERE id = ?').run(now, conversationId)
-
     return {
       id,
       conversationId,

src/stores/aiChat.ts

@@ -1205,6 +1205,17 @@ export const useAIChatStore = defineStore('aiChatRuntime', () => {
     content: string
   ): Promise<SendMessageResult> {
     try {
+      const hasConfig = await window.llmApi.hasConfig()
+      if (!hasConfig) {
+        return { success: false, reason: 'no_config' }
+      }
+      if (state.isAborted) {
+        return { success: false, reason: 'aborted' }
+      }
+      if (state.isAIThinking || activeTask.value) {
+        return { success: false, reason: 'busy', activeTask: activeTask.value }
+      }
+
       await useAIService().deleteMessagesFrom(state.currentConversationId!, originalMessage.id)
       targetBuffer.messages.splice(editIndex, targetBuffer.messages.length - editIndex)
       return sendMessage(chatKey, content)
@@ -1300,11 +1311,6 @@ export const useAIChatStore = defineStore('aiChatRuntime', () => {
         return { success: false, reason: 'busy', activeTask: activeTask.value }
       }
 
-      await useAIService().updateMessageContent(originalMessage.id, content)
-      if (hasOldAiResponse) {
-        await useAIService().deleteAndRelinkMessage(state.currentConversationId!, oldAiResponse.id)
-      }
-
       const context = {
         sessionId: state.sessionId,
         conversationId: state.currentConversationId!,
@@ -1407,6 +1413,16 @@ export const useAIChatStore = defineStore('aiChatRuntime', () => {
         updateAIMessage({ contentBlocks: [...blocks], isStreaming: false })
       }
 
+      if (!result.success) {
+        restoreOriginal()
+        return { success: false, reason: 'error' }
+      }
+
+      await useAIService().updateMessageContent(originalMessage.id, content)
+      if (hasOldAiResponse) {
+        await useAIService().deleteAndRelinkMessage(state.currentConversationId!, oldAiResponse.id)
+      }
+
       const serializableContentBlocks = targetBuffer.messages[aiMessageIndex].contentBlocks
         ? JSON.parse(JSON.stringify(targetBuffer.messages[aiMessageIndex].contentBlocks))
         : undefined
@@ -1428,6 +1444,14 @@ export const useAIChatStore = defineStore('aiChatRuntime', () => {
         content,
       }
 
+      const nextMsgIndex = aiMessageIndex + 1
+      if (nextMsgIndex < targetBuffer.messages.length) {
+        targetBuffer.messages[nextMsgIndex] = {
+          ...targetBuffer.messages[nextMsgIndex],
+          parentId: savedAiMsg.id,
+        }
+      }
+
       targetBuffer.sessionTokenUsage = await useAIService().getConversationTokenUsage(state.currentConversationId!)
       state.sessionTokenUsage = { ...targetBuffer.sessionTokenUsage }
       return { success: true }