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

crates/df-ai/src/openai_compat.rs

@@ -13,7 +13,7 @@ use serde::{Deserialize, Serialize};
 use tracing::{debug, error, warn};
 
 use crate::provider::{
-    CompletionRequest, CompletionResponse, LlmProvider, ProviderFeatures, StreamChunk, StreamResult,
+    CompletionRequest, CompletionResponse, LlmProvider, StreamChunk, StreamResult,
     TokenUsage, ToolCall, ToolCallDelta,
 };
 
@@ -148,6 +148,7 @@ pub(crate) fn apply_openai_sse(data: &str, usage_accum: &mut Option<TokenUsage>)
             finished: true,
             tool_calls: None,
             usage: usage_accum.take(),
+            error: None,
         };
     }
 
@@ -184,6 +185,7 @@ pub(crate) fn apply_openai_sse(data: &str, usage_accum: &mut Option<TokenUsage>)
                     finished,
                     tool_calls,
                     usage: None,
+                    error: None,
                 }
             } else {
                 // choices 为空 = usage-only chunk，不输出文本（usage 已累积）
@@ -192,6 +194,7 @@ pub(crate) fn apply_openai_sse(data: &str, usage_accum: &mut Option<TokenUsage>)
                     finished: false,
                     tool_calls: None,
                     usage: None,
+                    error: None,
                 }
             }
         }
@@ -202,6 +205,7 @@ pub(crate) fn apply_openai_sse(data: &str, usage_accum: &mut Option<TokenUsage>)
                 finished: false,
                 tool_calls: None,
                 usage: None,
+                error: None,
             }
         }
     }
@@ -233,7 +237,7 @@ impl OpenAICompatProvider {
             .connect_timeout(std::time::Duration::from_secs(30))
             .build()
             .unwrap_or_else(|e| {
-                warn!("reqwest builder 失败，降级为默认 client（无 connect_timeout）: {}", e);
+                warn!("reqwest builder 失败，回退默认 client: {}", e);
                 Client::new()
             });
         Self {
@@ -495,12 +499,8 @@ impl LlmProvider for OpenAICompatProvider {
         &self.default_model
     }
 
-    fn supported_features(&self) -> ProviderFeatures {
-        ProviderFeatures {
-            streaming: true,
-            function_calling: true,
-            vision: false,
-        }
+    fn endpoint(&self) -> String {
+        self.chat_url()
     }
 }