feat: 系统提示词改为单一入口统一管理

多个扩展各自整段改写系统提示词并按加载顺序接力，任一扩展定死提示词后
其余只能做字符串手术，且各上游的工具说明与组合包实际工具格局冲突。

- 新增 extensions/system-prompt.ts 作为唯一出口（加载列表最后），按
  config/prompt/（preamble.md、tools.jsonc、routing.jsonc、sections.jsonc）
  组合开场白、工具简介/规则与 <tool_routing> 分区；替代原封面与
  tool-routing 扩展，/dump-system-prompt 输出最终提示词。
- pi-chrome、pi-ssh、pi-hermes-memory 改为写命名分区，pi-rtk-optimizer
  改写 promptGuidelines，pi-permission-system 直接过滤结构化 skills，
  均不再返回 systemPrompt；pi-chrome 未授权时不再每轮冻结提示词。
- 新增 prompt-guard 代理加载第三方扩展（Hashline、FFF、LSP、
  context-mode）：拦截直接改写提示词并按目录覆盖工具说明；context-mode
  去掉与组合包路由冲突的锚点段，保留记忆与恢复快照。
- 消除冲突：bash 简介不再建议 grep/find；Hashline edit 不再称可用 grep
  锚点、不再介绍已关闭的 replace_text；context-mode 读写/网页路由提示。
- 守门测试：工具目录覆盖率、禁用用法检查、context-mode 上游原文锁定；
  AGENTS.md 新增「系统提示词单一所有权」。

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

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

pi-permission-system/test/handlers/before-agent-start.test.ts

@@ -18,6 +18,7 @@ function makeSetup() {
   return {
     handler,
     session,
+    permissionManager,
     configStore,
     forwarding,
     warmParser,
@@ -55,4 +56,35 @@ describe("AgentPrepHandler", () => {
     expect(result).toEqual({});
     expect(session.getActiveSkillEntries()).toEqual([]);
   });
+
+  it("filters denied skills out of structured systemPromptOptions.skills", async () => {
+    const { handler, session, permissionManager } = makeSetup();
+    vi.mocked(permissionManager.check).mockImplementation((intent) =>
+      makeCheckResult({
+        state:
+          intent.kind === "tool" &&
+          (intent.input as { name?: string })?.name === "dangerous"
+            ? "deny"
+            : "allow",
+      }),
+    );
+
+    const options = {
+      skills: [
+        { name: "librarian", description: "d", filePath: "/skills/librarian/SKILL.md", baseDir: "/skills/librarian" },
+        { name: "dangerous", description: "d", filePath: "/skills/dangerous/SKILL.md", baseDir: "/skills/dangerous" },
+        { name: "manual", description: "d", filePath: "/skills/manual/SKILL.md", baseDir: "/skills/manual", disableModelInvocation: true },
+      ],
+    };
+    const result = await handler.handle(
+      { systemPrompt: "You are an assistant.", systemPromptOptions: options },
+      makeCtx(),
+    );
+
+    expect(result).toEqual({});
+    expect(options.skills.map((skill) => skill.name)).toEqual(["librarian", "manual"]);
+    expect(session.getActiveSkillEntries().map((entry) => entry.name)).toEqual([
+      "librarian",
+    ]);
+  });
 });

pi-permission-system/test/skill-prompt-sanitizer.test.ts

@@ -7,6 +7,7 @@ import {
   findSkillPathMatch,
   parseAllSkillPromptSections,
   resolveSkillPromptEntries,
+  resolveStructuredSkillEntries,
   type SkillPermissionChecker,
 } from "#src/skill-prompt-sanitizer";
 import type { PermissionCheckResult } from "#src/types";
@@ -182,6 +183,92 @@ describe("resolveSkillPromptEntries", () => {
   });
 });
 
+// ── resolveStructuredSkillEntries ───────────────────────────────────────────
+
+describe("resolveStructuredSkillEntries", () => {
+  const makeSkill = (
+    name: string,
+    extra: Record<string, unknown> = {},
+  ): Record<string, unknown> => ({
+    name,
+    description: `Description of ${name}`,
+    filePath: `/skills/${name}/SKILL.md`,
+    baseDir: `/skills/${name}`,
+    disableModelInvocation: false,
+    ...extra,
+  });
+
+  test("filters denied skills out of the array and keeps them out of entries", () => {
+    const manager = makeManager("allow", { dangerous: "deny" });
+    const skills = [makeSkill("librarian"), makeSkill("dangerous")];
+    const result = resolveStructuredSkillEntries(
+      skills,
+      manager,
+      null,
+      normalizer,
+    );
+    expect(result.skills.map((skill) => skill.name)).toEqual(["librarian"]);
+    expect(result.entries.map((entry) => entry.name)).toEqual(["librarian"]);
+    expect(result.entries[0].state).toBe("allow");
+    expect(result.entries[0].location).toBe("/skills/librarian/SKILL.md");
+    expect(result.entries[0].normalizedBaseDir).toBe("/skills/librarian");
+  });
+
+  test("keeps disableModelInvocation skills in the array but out of entries", () => {
+    const manager = makeManager("allow");
+    const skills = [
+      makeSkill("visible"),
+      makeSkill("manual", { disableModelInvocation: true }),
+    ];
+    const result = resolveStructuredSkillEntries(
+      skills,
+      manager,
+      null,
+      normalizer,
+    );
+    expect(result.skills.map((skill) => skill.name)).toEqual([
+      "visible",
+      "manual",
+    ]);
+    expect(result.entries.map((entry) => entry.name)).toEqual(["visible"]);
+  });
+
+  test("passes through entries without a usable name", () => {
+    const manager = makeManager("deny");
+    const skills = [{ description: "no name" }];
+    const result = resolveStructuredSkillEntries(
+      skills,
+      manager,
+      null,
+      normalizer,
+    );
+    expect(result.skills).toHaveLength(1);
+    expect(manager.checkPermission).not.toHaveBeenCalled();
+  });
+
+  test("caches permission results per unique skill name", () => {
+    const manager = makeManager("allow");
+    const skills = [makeSkill("librarian"), makeSkill("librarian")];
+    resolveStructuredSkillEntries(skills, manager, null, normalizer);
+    expect(manager.checkPermission).toHaveBeenCalledTimes(1);
+  });
+
+  test("passes agentName to the permission check", () => {
+    const manager = makeManager("allow");
+    resolveStructuredSkillEntries(
+      [makeSkill("librarian")],
+      manager,
+      "my-agent",
+      normalizer,
+    );
+    expect(manager.checkPermission).toHaveBeenCalledWith(
+      "skill",
+      { name: "librarian" },
+      "my-agent",
+    );
+  });
+});
+
 // ── findSkillPathMatch ──────────────────────────────────────────────────────
 
 describe("findSkillPathMatch", () => {