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-chrome/extensions/chrome-profile-bridge/index.ts

@@ -923,11 +923,12 @@ export default function (pi: ExtensionAPI): void {
 
 	pi.on("before_agent_start", (event) => {
 		if (!chromeToolsRegistered || !chromeControlAuthorized()) {
-			return { systemPrompt: event.systemPrompt };
+			return;
 		}
-		const primer = `
-<chrome-profile-bridge>
-Chrome control is available through the chrome_* tools via a companion Chrome extension installed in the user's normal Chrome profile. Tools target the existing signed-in profile: no remote-debug port, no throwaway profile.
+		// Contribute structurally: the bundle's single system-prompt owner
+		// (extensions/system-prompt.ts) composes the final prompt; extensions
+		// must not return `systemPrompt` themselves.
+		const primer = `Chrome control is available through the chrome_* tools via a companion Chrome extension installed in the user's normal Chrome profile. Tools target the existing signed-in profile: no remote-debug port, no throwaway profile.
 
 Tab/window isolation (important):
 - pi-chrome owns a dedicated automation window/tab. When a chrome_* tool runs with no explicit target, it acts on that pi-chrome-owned target — it never reuses or overwrites the user's currently active tab. The dedicated target is created on first use and reused afterward.
@@ -948,9 +949,12 @@ Usage rules:
 5. \`chrome_navigate\` supports an optional \`initScript\` that runs at document_start in MAIN world for the next navigation (good for seeding localStorage or stubbing Date.now).
 6. By default chrome_* tools run in the background without focusing Chrome; pass \`background=false\` or run /chrome background off when the user wants to watch Chrome work.
 7. If you hit a native file-picker or privileged browser prompt gate, tell the user; generic clicks/typing/CSP gates are handled by Chrome input.
-8. Run /chrome doctor when in doubt about connectivity or capabilities.
-</chrome-profile-bridge>`;
-		return { systemPrompt: event.systemPrompt + primer };
+8. Run /chrome doctor when in doubt about connectivity or capabilities.`;
+		const promptOptions = event.systemPromptOptions as unknown as
+			| { sections?: Record<string, string> }
+			| undefined;
+		if (!promptOptions) return; // hosts without structured options just skip the section
+		(promptOptions.sections ??= {}).chrome_profile_bridge = primer;
 	});
 
 	// Shared handlers, dispatched by the unified /chrome command below.