重构: 后端 df-ai/commands 拆分+df-nodes/workflow 改造+P0 bug 修复

- df-ai: context 历史中毒三档自愈 sanitize_messages(AC3)+anthropic_compat tool_use_id None 跳过(AC1/AC2)+删 router/stream 死码
- df-core: events 加 select_type+decisions 多选审批契约(F-260615-01)
- df-execute: shell run_command 工具复用(F-260615-05)
- df-nodes: human_node 多选校验+2 端到端测(F-01)+取消跳 set_failed(B-03b-R1/R2/R8)
- df-workflow: executor/dag/state cancel 闭环(B-06/07/03a/b)+provider approve options(R-PD-5)
- df-storage: find_path_conflict 抽公共(R-PD-11)+COLS 常量断言
- df-ideas: 删 IdeaPromoter/PromotionPolicy 死码(R-PD-14)
- src-tauri/commands/ai: secret keyring 迁移(FR-S1/R-PD-4)+GeneratingGuard RAII+disarm(B-09/26)+newConversation 软复位(B-10)+stream 心跳/stop select/空回复判错(B-02/04/05/15)+run_command(F-05)+mask audit(AR-3)
- src-tauri/commands/{project,task,workflow,mod,lib,state}: task detail IPC(F-02)+approve decisions+task list 联动(B-29)
- Cargo.lock+Cargo.toml 依赖同步

src-tauri/src/commands/ai/title.rs

@@ -57,12 +57,17 @@ pub(crate) async fn ensure_conversation_title(
     }
 
     // 标题生成是独立一次 LLM 调用，自建 provider（便于后台 spawn，不借主 loop 的 &dyn LlmProvider）
-    let provider: Box<dyn LlmProvider> = df_ai::build_provider(
-        &provider_config.provider_type,
-        &provider_config.base_url,
-        &provider_config.api_key,
-        &provider_config.default_model,
-    );
+    // build_provider_for 含空 key 早失败:Err(如 keyring 读不到)→ 跳过 LLM,extract_title 兜底
+    let provider: Box<dyn LlmProvider> = match super::secret::build_provider_for(provider_config) {
+        Ok(p) => p,
+        Err(e) => {
+            tracing::warn!("标题生成跳过(provider 密钥不可用,走 extract_title 兜底): {}", e);
+            let title = extract_title(&all_msgs).unwrap_or_else(|| "新对话".to_string());
+            let _ = conv_repo.update_field(conv_id, "title", &title).await;
+            let _ = app_handle.emit("ai-conversation-changed", ());
+            return;
+        }
+    };
     let title = match generate_title_via_llm(&*provider, &provider_config.default_model, summary_msgs, &llm_concurrency).await {
         Some(t) => t,
         None => extract_title(&all_msgs).unwrap_or_else(|| "新对话".to_string()),