feat: Batch 5-9 — GrowthIntegration桥接、验证补全、死代码清理、Pipeline模板、Speech/Twitter真实实现

Batch 5 (P0): GrowthIntegration 接入 Tauri
- Kernel 新增 set_viking()/set_extraction_driver() 桥接 SqliteStorage
- 中间件链共享存储，MemoryExtractor 接入 LLM 驱动

Batch 6 (P1): 输入验证 + Heartbeat
- Relay 验证补全（stream 兼容检查、API key 格式校验）
- UUID 类型校验、SessionId 错误返回
- Heartbeat 默认开启 + 首次聊天自动初始化

Batch 7 (P2): 死代码清理
- zclaw-channels 整体移除（317 行）
- multi-agent 特性门控、admin 方法标注

Batch 8 (P2): Pipeline 模板
- PipelineMetadata 新增 annotations 字段
- pipeline_templates 命令 + 2 个示例模板
- fallback driver base_url 修复（doubao/qwen/deepseek 端点）

Batch 9 (P1): SpeechHand/TwitterHand 真实实现
- SpeechHand: tts_method 字段 + Browser TTS 前端集成 (Web Speech API)
- TwitterHand: 12 个 action 全部替换为 Twitter API v2 真实 HTTP 调用
- chatStore/useAutomationEvents 双路径 TTS 触发

desktop/src-tauri/src/lib.rs

@@ -1352,15 +1352,19 @@ pub fn run() {
             kernel_commands::scheduled_task_create,
             kernel_commands::scheduled_task_list,
 
-            // A2A commands (Agent-to-Agent messaging)
+            // A2A commands gated behind multi-agent feature
+            #[cfg(feature = "multi-agent")]
             kernel_commands::agent_a2a_send,
+            #[cfg(feature = "multi-agent")]
             kernel_commands::agent_a2a_broadcast,
+            #[cfg(feature = "multi-agent")]
             kernel_commands::agent_a2a_discover,
+            #[cfg(feature = "multi-agent")]
             kernel_commands::agent_a2a_delegate_task,
 
             // Pipeline commands (DSL-based workflows)
             pipeline_commands::pipeline_list,
-            pipeline_commands::pipeline_get,
+            pipeline_commands::pipeline_templates,            pipeline_commands::pipeline_get,
             pipeline_commands::pipeline_run,
             pipeline_commands::pipeline_progress,
             pipeline_commands::pipeline_cancel,