feat(prompt): 重新注册 bash，把"不要用 bash 搜索"写进工具描述

真实会话里模型仍习惯性先调 bash grep，被拒后才改用 grep 工具；系统提示词里已有 4 处
提醒，但模型下调用决定时看的是工具 schema 描述，而 Pi 内置 bash 描述对此只字未提。

- 新增 extensions/bash-override.ts：用 Pi 的 createBashToolDefinition 重新注册 bash，
  执行、输出结构与 codemode 说明完全沿用上游；shellPath/commandPrefix 按 ctx.cwd
  经 SettingsManager 惰性解析，与内置一致
- tools.jsonc 新增 descriptionAppend 字段，由 prompt-guard 注册时拼接到上游描述后
- bash 增加命令→工具对照规则（grep -n / grep -rl / find -name），并提示
  文件清单用 $(git ls-files) 传参、不要接 xargs（会触发权限审核）

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

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

extensions/system-prompt-config.ts

@@ -10,7 +10,12 @@ import { fileURLToPath } from "node:url";
 /** Entry in `config/prompt/tools.jsonc`. */
 export type ToolCatalogEntry =
 	| { inherit: true }
-	| { snippet?: string | null; guidelines?: string[]; description?: string };
+	| {
+			snippet?: string | null;
+			guidelines?: string[];
+			description?: string;
+			descriptionAppend?: string;
+	  };
 
 export interface ToolCatalog {
 	version: 1;
@@ -152,7 +157,7 @@ function isStringArray(value: unknown): value is string[] {
 	return Array.isArray(value) && value.every((entry) => typeof entry === "string");
 }
 
-const TOOL_ENTRY_KEYS = new Set(["inherit", "snippet", "guidelines", "description"]);
+const TOOL_ENTRY_KEYS = new Set(["inherit", "snippet", "guidelines", "description", "descriptionAppend"]);
 
 function validateToolEntry(name: string, raw: unknown): ToolCatalogEntry {
 	if (!isPlainObject(raw)) {
@@ -170,9 +175,9 @@ function validateToolEntry(name: string, raw: unknown): ToolCatalogEntry {
 		return { inherit: true };
 	}
 	const hasField =
-		"snippet" in raw || "guidelines" in raw || "description" in raw;
+		"snippet" in raw || "guidelines" in raw || "description" in raw || "descriptionAppend" in raw;
 	if (!hasField) {
-		fail("tools.jsonc", `tool "${name}" needs "inherit": true or at least one of snippet/guidelines/description`);
+		fail("tools.jsonc", `tool "${name}" needs "inherit": true or at least one of snippet/guidelines/description/descriptionAppend`);
 	}
 	if ("snippet" in raw && raw.snippet !== null && typeof raw.snippet !== "string") {
 		fail("tools.jsonc", `tool "${name}".snippet must be a string or null`);
@@ -183,10 +188,13 @@ function validateToolEntry(name: string, raw: unknown): ToolCatalogEntry {
 	if ("description" in raw && typeof raw.description !== "string") {
 		fail("tools.jsonc", `tool "${name}".description must be a string`);
 	}
+	if ("descriptionAppend" in raw && typeof raw.descriptionAppend !== "string") {
+		fail("tools.jsonc", `tool "${name}".descriptionAppend must be a string`);
+	}
 	return raw as ToolCatalogEntry;
 }
 
-function validateToolCatalog(raw: unknown): ToolCatalog {
+export function validateToolCatalog(raw: unknown): ToolCatalog {
 	if (!isPlainObject(raw) || raw.version !== 1 || !isPlainObject(raw.tools)) {
 		fail("tools.jsonc", 'expected { "version": 1, "tools": { ... } }');
 	}
@@ -321,8 +329,8 @@ export function isSubagentCustomPrompt(customPrompt: unknown): boolean {
  * Apply the tool catalog to the mutable prompt options: a `snippet` string
  * replaces the tool's `<tools>` line (`null` hides it), `guidelines` replaces
  * the tool's `<rules>` lines; `{inherit:true}` entries are left untouched.
- * `description` is not applied here — it is a registration-time concern handled
- * by `extensions/prompt-guard.ts`.
+ * `description` and `descriptionAppend` are not applied here — they are
+ * registration-time concerns handled by `extensions/prompt-guard.ts`.
  *
  * Returns the selected tool names that have no catalog entry at all.
  */