Add thread execution conflict guards to chat flows

src/app/api/v1/projects/[projectId]/messages/route.ts

@@ -2,10 +2,12 @@ import { NextRequest, NextResponse } from "next/server";
 import { requireRequestSession } from "@/lib/boss-auth";
 import { appendProjectMessage, buildCollaborationGate, readState } from "@/lib/boss-data";
 import {
+  getThreadConversationExecutionConflict,
   queueGroupDispatchPlan,
   queueThreadConversationReplyTask,
   replyToMasterAgentUserMessage,
   shouldRecommendMasterAgentDispatchPlan,
+  ThreadConversationExecutionConflictError,
 } from "@/lib/boss-master-agent";
 import { evaluatePermissionPolicy } from "@/lib/execution/permission-policy";
 
@@ -26,6 +28,8 @@ function threadConversationFailureMessage(error?: string) {
       return "当前线程还没有绑定真实 Codex 线程，请先重新导入该线程后再试。";
     case "THREAD_TARGET_DEVICE_OFFLINE":
       return "当前线程所在设备不在线，请先让对应设备上线后再试。";
+    case "THREAD_EXECUTION_CONFLICT":
+      return "当前线程命中了 GUI / CLI 冲突保护，请先确认本项目是否放行后再继续发送。";
     default:
       return error ?? "UNKNOWN_ERROR";
   }
@@ -80,6 +84,27 @@ export async function POST(
       );
     }
 
+    const singleThreadExecutionConflict =
+      project &&
+      projectId !== "master-agent" &&
+      !project.isGroup &&
+      (body.kind ?? "text") === "text" &&
+      (body.body ?? "").trim().length > 0
+        ? await getThreadConversationExecutionConflict(projectId)
+        : null;
+
+    if (singleThreadExecutionConflict) {
+      return NextResponse.json(
+        {
+          ok: false,
+          code: "THREAD_EXECUTION_CONFLICT",
+          message: threadConversationFailureMessage("THREAD_EXECUTION_CONFLICT"),
+          executionConflict: singleThreadExecutionConflict,
+        },
+        { status: 409 },
+      );
+    }
+
     const message = await appendProjectMessage({
       projectId,
       senderLabel: session.displayName || "你",
@@ -209,6 +234,17 @@ export async function POST(
       collaborationGate,
     });
   } catch (error) {
+    if (error instanceof ThreadConversationExecutionConflictError) {
+      return NextResponse.json(
+        {
+          ok: false,
+          code: error.message,
+          message: threadConversationFailureMessage(error.message),
+          executionConflict: error.conflict,
+        },
+        { status: 409 },
+      );
+    }
     const reason = error instanceof Error ? error.message : "UNKNOWN_ERROR";
     return NextResponse.json(
       {