Carry output format and tool surface on delegation requests (Q3 WP3)

Why: the delegation task brief must state goal, output format, tools and
boundaries (Q3 acceptance); Request had no carriers for the two new
sections, so delegate_task callers could not declare them.

Evidence: TestDelegateToolRoundTrip extended to assert output_format and
tools survive the tool-call round trip; runtime suite green (SELF); CI
authoritative (GATE).

Impact: additive Request fields + delegate_task schema/description; empty
fields keep today's behavior (task brief sections omitted).

Refs: Q3 plan WP3; Dev card .task/feature-agent-stack-q3.md

runtime/subagent/subagent.go

@@ -27,6 +27,13 @@ type Request struct {
 	NonGoals     string   `json:"non_goals,omitempty"`
 	DoneCriteria string   `json:"done_criteria,omitempty"`
 	Deliverables []string `json:"deliverables,omitempty"`
+	// OutputFormat 交付物的结构/格式要求（Q3 WP3：委派模板四要素之一，
+	// 任务书「输出格式」节；空 = 由子代理自行决定）。
+	OutputFormat string `json:"output_format,omitempty"`
+	// Tools 允许子代理使用的工具面（Q3 WP3：任务书「工具面」节；空 = 沿用
+	// 子代理画像默认。宿主可按此收窄，不得用于扩权——子代理权限恒不超过
+	// 委派方）。
+	Tools []string `json:"tools,omitempty"`
 	// Deadline / MaxToolCalls 是宿主注入的预算余量（模型不可自行扩权）。
 	Deadline     time.Time `json:"-"`
 	MaxToolCalls int       `json:"-"`
@@ -67,7 +74,7 @@ func RegisterWithHooks(r *tools.Registry, factory Factory, bus *hooks.Bus) {
 
 func (t *delegateTool) Name() string { return "delegate_task" }
 func (t *delegateTool) Description() string {
-	return "Delegate a self-contained subtask to a fresh sub-agent. Fill every field: goal, inputs (with versions), write_scope (directory the sub-agent may write), non_goals, done_criteria, deliverables. The sub-agent cannot exceed your permissions; report back its conclusion and files."
+	return "Delegate a self-contained subtask to a fresh sub-agent. Fill every field: goal, inputs (with versions), write_scope (directory the sub-agent may write), non_goals, done_criteria, deliverables, output_format (structure/format the deliverables must follow), tools (tool names the sub-agent should use). The sub-agent cannot exceed your permissions; report back its conclusion and files."
 }
 func (t *delegateTool) Parameters() json.RawMessage {
 	return json.RawMessage(`{"type":"object","required":["goal","done_criteria"],"properties":{
@@ -77,6 +84,8 @@ func (t *delegateTool) Parameters() json.RawMessage {
 		"non_goals":{"type":"string"},
 		"done_criteria":{"type":"string"},
 		"deliverables":{"type":"array","items":{"type":"string"}},
+		"output_format":{"type":"string"},
+		"tools":{"type":"array","items":{"type":"string"}},
 		"background":{"type":"boolean"}
 	}}`)
 }

runtime/subagent/subagent_test.go

@@ -36,7 +36,9 @@ func TestDelegateToolRoundTrip(t *testing.T) {
 		"write_scope":"research/",
 		"non_goals":"不做实现",
 		"done_criteria":"产出三来源对照表",
-		"deliverables":["notes.md","data/table.csv"]
+		"deliverables":["notes.md","data/table.csv"],
+		"output_format":"Markdown：结论先行，附三来源对照表",
+		"tools":["web_search","read_file"]
 	}`))
 	if res.IsError {
 		t.Fatal(res.Content)
@@ -44,6 +46,11 @@ func TestDelegateToolRoundTrip(t *testing.T) {
 	if got.Goal != "调研主题 X" || got.WriteScope != "research/" || got.DoneCriteria != "产出三来源对照表" {
 		t.Fatalf("delegation fields lost: %+v", got)
 	}
+	// Q3 WP3：输出格式与工具面随委派请求透传（任务书两节的声明源）。
+	if got.OutputFormat != "Markdown：结论先行，附三来源对照表" ||
+		strings.Join(got.Tools, ",") != "web_search,read_file" {
+		t.Fatalf("output_format/tools lost: %+v", got)
+	}
 	if !strings.Contains(res.Content, "[sub-agent succeeded]") ||
 		!strings.Contains(res.Content, "调研完成") ||
 		!strings.Contains(res.Content, "files: data/table.csv, notes.md") {