feat(pi-subagents): 重新启用子 Agent 并使用独立的子 Agent 提示词

- 根包恢复 file:./pi-subagents 依赖与 extensions/subagents.ts 加载
  （排在 permission-system 之后、Tool Search 之前），并刷新根锁文件；
  Agent / get_subagent_result / steer_subagent 权限设为 allow，
  子 Agent 内的实际操作仍逐个经权限系统并转发主会话。
- 新增 config/prompt/subagent/：执行者角色 preamble 与组合包自带的
  general-purpose / Explore / Plan 定义（替换上游内置，去掉 bash find
  冲突规则与写死的 Haiku 模型）。
- pi-subagents 新增 basePrompt / bundledAgentsDir / excludedExtensionPaths
  选项：子 Agent 不再嵌入父会话提示词，身份标记置于开头；子会话排除
  pi-ask-user。未传选项时保持上游行为。
- system-prompt.ts：customPrompt 自带开场白时不再覆盖（修复子 Agent 角色
  与 <active_agent> 身份被抹掉）；仅凭 customPrompt 上的 <active_agent>
  识别子会话，routing 规则支持 scope，sections 支持 subagentExclude
  （子会话去掉 memory_policy 与 chrome_profile_bridge）。
- pi-hermes-memory：子会话只读，记忆/skill 写入工具返回错误，后台整理、
  纠错检测、会话 flush 与索引写入全部跳过。

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

extensions/system-prompt-config.ts

@@ -20,6 +20,8 @@ export interface ToolCatalog {
 export interface RoutingRule {
 	whenAll?: string[];
 	whenAny?: string[];
+	/** Which sessions the rule renders for; absent means both. */
+	scope?: "main" | "subagent";
 	text: string;
 }
 
@@ -31,6 +33,8 @@ export interface RoutingConfig {
 export interface SectionsConfig {
 	version: 1;
 	order: string[];
+	/** Contributed sections removed from subagent (customPrompt) sessions. */
+	subagentExclude: string[];
 }
 
 /**
@@ -64,6 +68,14 @@ export function resolveSectionsPath(): string {
 	return fileURLToPath(new URL("sections.jsonc", PROMPT_CONFIG_DIR));
 }
 
+export function resolveSubagentPreamblePath(): string {
+	return fileURLToPath(new URL("subagent/preamble.md", PROMPT_CONFIG_DIR));
+}
+
+export function resolveSubagentAgentsDir(): string {
+	return fileURLToPath(new URL("subagent/agents/", PROMPT_CONFIG_DIR));
+}
+
 /**
  * Strip `//` and `/* ... *\/` comments while respecting string literals, so a
  * `//` inside a quoted value (for example `"https://…"`) is never removed.
@@ -185,7 +197,7 @@ function validateToolCatalog(raw: unknown): ToolCatalog {
 	return { version: 1, tools };
 }
 
-const ROUTING_RULE_KEYS = new Set(["whenAll", "whenAny", "text"]);
+const ROUTING_RULE_KEYS = new Set(["whenAll", "whenAny", "scope", "text"]);
 
 function validateRoutingRule(index: number, raw: unknown): RoutingRule {
 	if (!isPlainObject(raw)) {
@@ -205,10 +217,13 @@ function validateRoutingRule(index: number, raw: unknown): RoutingRule {
 	if ("whenAny" in raw && !isStringArray(raw.whenAny)) {
 		fail("routing.jsonc", `rule #${index}.whenAny must be an array of strings`);
 	}
+	if ("scope" in raw && raw.scope !== "main" && raw.scope !== "subagent") {
+		fail("routing.jsonc", `rule #${index}.scope must be "main" or "subagent"`);
+	}
 	return raw as RoutingRule;
 }
 
-function validateRoutingConfig(raw: unknown): RoutingConfig {
+export function validateRoutingConfig(raw: unknown): RoutingConfig {
 	if (!isPlainObject(raw) || raw.version !== 1 || !Array.isArray(raw.rules)) {
 		fail("routing.jsonc", 'expected { "version": 1, "rules": [ ... ] }');
 	}
@@ -220,7 +235,7 @@ function validateRoutingConfig(raw: unknown): RoutingConfig {
 
 const SECTION_NAME_PATTERN = /^[a-z][a-z0-9_-]*$/;
 
-function validateSectionsConfig(raw: unknown): SectionsConfig {
+export function validateSectionsConfig(raw: unknown): SectionsConfig {
 	if (!isPlainObject(raw) || raw.version !== 1 || !isStringArray(raw.order)) {
 		fail("sections.jsonc", 'expected { "version": 1, "order": [ ... ] }');
 	}
@@ -229,7 +244,19 @@ function validateSectionsConfig(raw: unknown): SectionsConfig {
 			fail("sections.jsonc", `"${name}" is not a valid section name`);
 		}
 	}
-	return { version: 1, order: raw.order };
+	if ("subagentExclude" in raw && !isStringArray(raw.subagentExclude)) {
+		fail("sections.jsonc", `"subagentExclude" must be an array of section names`);
+	}
+	for (const name of raw.subagentExclude ?? []) {
+		if (!SECTION_NAME_PATTERN.test(name) || name === "preamble") {
+			fail("sections.jsonc", `"subagentExclude" entry "${name}" is not a valid section name`);
+		}
+	}
+	return {
+		version: 1,
+		order: raw.order,
+		subagentExclude: isStringArray(raw.subagentExclude) ? raw.subagentExclude : [],
+	};
 }
 
 export function loadToolCatalog(): ToolCatalog {
@@ -262,6 +289,34 @@ export function readPreamble(): string | undefined {
 	return trimmed.length > 0 ? trimmed : undefined;
 }
 
+/**
+ * Read the bundle's subagent base preamble (`config/prompt/subagent/preamble.md`),
+ * re-read on each call so the file is never cached between spawns.
+ * Blank or missing → `undefined`, which keeps pi-subagents' upstream composition.
+ */
+export function readSubagentPreamble(): string | undefined {
+	let raw: string;
+	try {
+		raw = readFileSync(resolveSubagentPreamblePath(), "utf8");
+	} catch {
+		return undefined;
+	}
+	const trimmed = raw.replace(/\s+$/, "");
+	return trimmed.length > 0 ? trimmed : undefined;
+}
+
+/**
+ * The `<active_agent name="..."/>` tag pi-subagents stamps into every child
+ * prompt — tested ONLY against `systemPromptOptions.customPrompt`, never the
+ * rendered prompt: a main session may contain the literal tag via project
+ * docs and must still be treated as main.
+ */
+const ACTIVE_AGENT_TAG = /<active_agent\s+name=["'][^"']+["'][^>]*>/i;
+
+export function isSubagentCustomPrompt(customPrompt: unknown): boolean {
+	return typeof customPrompt === "string" && ACTIVE_AGENT_TAG.test(customPrompt);
+}
+
 /**
  * Apply the tool catalog to the mutable prompt options: a `snippet` string
  * replaces the tool's `<tools>` line (`null` hides it), `guidelines` replaces
@@ -302,11 +357,19 @@ export function applyToolCatalog(options: MutablePromptOptions, catalog: ToolCat
  * `whenAny` tool is active (a rule with neither always applies). An absent
  * `selectedTools` means every tool counts as active, matching the previous
  * tool-routing behavior.
+ *
+ * `audience` filters `scope`: rules without a scope render for both "main"
+ * and "subagent" sessions, scoped rules only for their own audience.
  */
-export function renderRouting(rules: RoutingRule[], selectedTools: string[] | undefined): string {
+export function renderRouting(
+	rules: RoutingRule[],
+	selectedTools: string[] | undefined,
+	audience: "main" | "subagent" = "main",
+): string {
 	const isActive = (name: string) => selectedTools === undefined || selectedTools.includes(name);
 	const lines: string[] = [];
 	for (const rule of rules) {
+		if (rule.scope !== undefined && rule.scope !== audience) continue;
 		if (rule.whenAll !== undefined && !rule.whenAll.every(isActive)) continue;
 		if (rule.whenAny !== undefined && !rule.whenAny.some(isActive)) continue;
 		lines.push(`- ${rule.text}`);