增强: 任务查询支持按状态过滤(list_tasks status)

- AI 工具 list_tasks: schema 加 status 参数 + handler 内存过滤
  (todo/in_progress/in_review/testing/blocked/done/cancelled)
- df-mcp list_tasks: handler 加 status 过滤(MCP 对外一致)
  (spec 声明待补:中文 Edit 编码匹配限制,后续补)

自验: workspace EXIT 0 + df-mcp cargo check EXIT 0

crates/df-mcp/src/tools.rs

@@ -346,12 +346,16 @@ fn bind_directory(ctx: &Ctx, args: Value) -> BoxFuture<'static, CallToolResult>
 fn list_tasks(ctx: &Ctx, args: Value) -> BoxFuture<'static, CallToolResult> {
     let db = ctx.db.clone();
     let project_id_filter = args.get("project_id").and_then(|v| v.as_str()).map(|s| s.to_owned());
+    let status_filter = args.get("status").and_then(|v| v.as_str()).map(|s| s.to_owned());
     Box::pin(async move {
         let repo = TaskRepo::new(&db);
         match repo.list_active().await {
             Ok(mut list) => {
-                if let Some(pid) = project_id_filter {
+                if let Some(pid) = &project_id_filter {
-                    list.retain(|t| t.project_id == pid);
+                    list.retain(|t| t.project_id == *pid);
+                }
+                if let Some(st) = &status_filter {
+                    list.retain(|t| t.status == *st);
                 }
                 json_ok(json!({ "tasks": list, "count": list.len() }))
             }

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

@@ -605,17 +605,21 @@ fn register_project_tools(registry: &mut AiToolRegistry, db: &Arc<Database>) {
 /// 组内顺序保留原相对顺序(list/create/update/advance/delete/get_count)。
 fn register_task_tools(registry: &mut AiToolRegistry, db: &Arc<Database>) {
     registry.register(
-        "list_tasks", "列出任务，可按 project_id 筛选，支持 offset/limit 分页。返回 items、total、has_more。默认 limit=50",
+        "list_tasks", "列出任务，可按 project_id/status 筛选(status: todo/in_progress/in_review/testing/blocked/done/cancelled)，支持 offset/limit 分页。返回 items、total、has_more。默认 limit=50",
-        df_ai::ai_tools::object_schema(vec![("project_id", "string", false), ("offset", "integer", false), ("limit", "integer", false)]), RiskLevel::Low,
+        df_ai::ai_tools::object_schema(vec![("project_id", "string", false), ("status", "string", false), ("offset", "integer", false), ("limit", "integer", false)]), RiskLevel::Low,
         { let db = db.clone(); Box::new(move |args: serde_json::Value| {
             let db = db.clone();
             Box::pin(async move {
                 let repo = df_storage::crud::TaskRepo::new(&db);
-                let tasks = if let Some(pid) = args.get("project_id").and_then(|v| v.as_str()) {
+                let mut tasks = if let Some(pid) = args.get("project_id").and_then(|v| v.as_str()) {
                     repo.query("project_id", pid).await?
                 } else {
                     repo.list_all().await?
                 };
+                // 按状态过滤(可选):todo/in_progress/in_review/testing/blocked/done/cancelled
+                if let Some(status) = args.get("status").and_then(|v| v.as_str()) {
+                    tasks.retain(|t| t.status == status);
+                }
                 let total = tasks.len();
                 let offset = args["offset"].as_u64().unwrap_or(0) as usize;
                 let limit = args["limit"].as_u64().unwrap_or(MAX_LIST_RESULTS as u64).min(MAX_LIST_RESULTS as u64) as usize;