refactor: 移除 context-mode，Chrome 快照改为直接返回

context-mode 的 ctx_execute 系工具以真实 shell 执行且权限为 allow，绕过了
bash 策略与 protectedWrites；其每轮注入、独立 MCP 子进程与 skills 也与组合包
提示词单一所有权冲突。大输出职责已由 pi-overflow（入口截断）与
pi-compaction（压力遮蔽）承担：
- 删除 context-mode 依赖、wrapper/过滤器、skills，以及 ctx_* 的权限、
  tools.jsonc、路由规则、tool-search 常驻与 4 个分组
- better-sqlite3@12 仅为 context-mode 传递依赖，随之移除根 allowScripts
- pi-chrome：按用户决定移除快照隐私规则与 .pi/chrome-context 临时文件机制，
  快照 JSON 直接作为工具结果返回、details 只留小型元数据，超长由 pi-overflow
  截断并用 overflow_query 提取；授权生命周期不变

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

pi-tool-search/test/extension.test.ts

@@ -254,9 +254,9 @@ test("uses the precomputed bundle groups without calling a model", async () => {
       sourceTool("read", "Read a file"),
       sourceTool("web_search", "Search broadly for current web sources"),
       sourceTool("web_fetch", "Fetch a selected web source"),
-      sourceTool("ctx_execute", "Run commands in a context sandbox"),
-      sourceTool("ctx_execute_file", "Analyze a file in a context sandbox"),
-      sourceTool("ctx_batch_execute", "Run a bounded command batch"),
+      sourceTool("context_tree_query", "Inspect the context tree ledger"),
+      sourceTool("overflow_query", "Inspect a stored oversized tool result"),
+      sourceTool("memory_search", "Search durable memories"),
     ];
     const api = {
       getAllTools: () => sourceTools,
@@ -280,7 +280,7 @@ test("uses the precomputed bundle groups without calling a model", async () => {
       } as unknown as ExtensionContext["modelRegistry"],
     });
     handlers.get("session_start")?.({}, ctx);
-    assert.ok(["ctx_execute", "ctx_execute_file", "ctx_batch_execute"].every((name) => activeCalls.at(-1)?.includes(name)));
+    assert.ok(["context_tree_query", "overflow_query", "memory_search"].every((name) => activeCalls.at(-1)?.includes(name)));
 
     const ambiguous = await registered.get("tool_search")?.execute(
       "call-1",