修复: B-22 前后端状态同步(ai_is_generating IPC+发送前查后端真值)

commands.rs 加 ai_is_generating IPC(读 session.generating)+lib.rs 注册;useAiSend sendMessage 预检先 invoke('ai_is_generating')查后端真值:后端 generating=true 时入队(撞 QUEUE_LIMIT 抛错)+本地 streaming=false 则复位 streaming=true 让用户感知,IPC 失败退化为 false 不阻断。消除前端 streaming 与后端 generating 不同步致预检放行撞拦截。批6 w8qbkxxvz,cargo+vue-tsc 0

src-tauri/src/lib.rs

@@ -73,6 +73,7 @@ pub fn run() {
             commands::ai::ai_approve,
             commands::ai::ai_pending_tool_calls,
             commands::ai::ai_chat_clear,
+            commands::ai::ai_is_generating,
             commands::ai::ai_list_providers,
             commands::ai::ai_save_provider,
             commands::ai::ai_set_provider,