feat: codegraph_explore 改为原生 CLI 工具并移除 /plugin_init

codegraph 有一等公民 CLI 且上游保证其输出与 codegraph_explore MCP
工具一致，走共享 MCP adapter 只是多余的传输层。改为原生 Pi 工具后
每次调用以短命 codegraph explore 进程完成，去掉常驻 server/daemon；
未初始化项目经 ctx.ui.confirm 确认后 init 并自动重试，拒绝或失败时
打回并引导模型回退 find/grep/read/LSP；结果按 codegraph.db mtime
做有界缓存，索引一变即失效。共享 MCP adapter 只保留 Exa；工具名
不变，权限策略、Tool Search 常驻表、路由规则与分组不受影响。

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

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

tests/codegraph.test.ts

@@ -0,0 +1,208 @@
+import assert from "node:assert/strict";
+import { mkdir, mkdtemp, rm, utimes, writeFile } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import test from "node:test";
+
+import {
+	buildExploreArgs,
+	createCodegraphExploreHandler,
+	findIndexedRoot,
+	isNotIndexedOutput,
+	type CodegraphExec,
+	type ExploreParams,
+} from "../extensions/codegraph.ts";
+
+async function makeIndexedProject(): Promise<{ root: string; cleanup: () => Promise<void> }> {
+	const root = await mkdtemp(join(tmpdir(), "my-pi-codegraph-"));
+	await mkdir(join(root, ".codegraph"));
+	await writeFile(join(root, ".codegraph", "codegraph.db"), "");
+	return { root, cleanup: () => rm(root, { recursive: true, force: true }) };
+}
+
+function mockCtx(cwd: string, confirm?: () => Promise<boolean>) {
+	return {
+		cwd,
+		hasUI: confirm !== undefined,
+		ui: { confirm: confirm ?? (async () => false) },
+	} as never;
+}
+
+function mockExec(handler: (command: string, args: string[]) => { code?: number; stdout?: string; stderr?: string }) {
+	const calls: Array<{ command: string; args: string[] }> = [];
+	const exec: CodegraphExec = async (command, args) => {
+		calls.push({ command, args });
+		const result = handler(command, args);
+		return { code: result.code ?? 0, stdout: result.stdout ?? "", stderr: result.stderr ?? "", killed: false };
+	};
+	return { exec, calls };
+}
+
+function makeHandler(exec: CodegraphExec) {
+	return {
+		handle: createCodegraphExploreHandler(exec, new Map(), new Map()),
+	};
+}
+
+test("findIndexedRoot locates the nearest ancestor index", async () => {
+	const { root, cleanup } = await makeIndexedProject();
+	try {
+		const nested = join(root, "src", "deep");
+		await mkdir(nested, { recursive: true });
+		assert.equal(await findIndexedRoot(nested), root);
+		assert.equal(await findIndexedRoot(root), root);
+	} finally {
+		await cleanup();
+	}
+});
+
+test("findIndexedRoot returns undefined when no index exists", async () => {
+	const root = await mkdtemp(join(tmpdir(), "my-pi-codegraph-"));
+	try {
+		assert.equal(await findIndexedRoot(root), undefined);
+	} finally {
+		await rm(root, { recursive: true, force: true });
+	}
+});
+
+test("buildExploreArgs maps params to CLI argv", () => {
+	assert.deepEqual(buildExploreArgs({ query: "auth flow" }, "/repo"), ["explore", "-p", "/repo", "auth flow"]);
+	assert.deepEqual(
+		buildExploreArgs({ query: "q", maxFiles: 5, projectPath: "/ignored" }, "/repo"),
+		["explore", "-p", "/repo", "--max-files", "5", "q"],
+	);
+});
+
+test("isNotIndexedOutput detects the upstream marker", () => {
+	assert.equal(isNotIndexedOutput("✗ CodeGraph isn't available here — no .codegraph/ index exists in /x."), true);
+	assert.equal(isNotIndexedOutput("Found 3 symbols"), false);
+});
+
+test("explore runs the CLI and caches by database mtime", async () => {
+	const { root, cleanup } = await makeIndexedProject();
+	const { exec, calls } = mockExec(() => ({ stdout: "explore output" }));
+	const { handle } = makeHandler(exec);
+	try {
+		const first = await handle({ query: "auth" }, mockCtx(root));
+		assert.equal(first.content[0].text, "explore output");
+		const second = await handle({ query: "auth" }, mockCtx(root));
+		assert.equal(second.content[0].text, "explore output");
+		assert.equal(calls.length, 1, "identical query on unchanged index must hit the cache");
+
+		// Simulate a reindex: bump the db mtime.
+		await utimes(join(root, ".codegraph", "codegraph.db"), new Date(), new Date(Date.now() + 5000));
+		await handle({ query: "auth" }, mockCtx(root));
+		assert.equal(calls.length, 2, "mtime change must invalidate the cached result");
+	} finally {
+		await cleanup();
+	}
+});
+
+test("uninitialized project asks the user and indexes on approval", async () => {
+	const root = await mkdtemp(join(tmpdir(), "my-pi-codegraph-"));
+	const { exec, calls } = mockExec((_command, args) => {
+		if (args[0] === "init") {
+			// Emulate codegraph init creating the index.
+			return { stdout: "indexed" };
+		}
+		return { stdout: "explore output" };
+	});
+	const { handle } = makeHandler(exec);
+	try {
+		const result = await handle({ query: "auth" }, mockCtx(root, async () => true));
+		assert.equal(result.content[0].text, "explore output");
+		assert.deepEqual(
+			calls.map(({ args }) => args[0]),
+			["init", "explore"],
+		);
+		assert.deepEqual(calls[0].args, ["init", root]);
+	} finally {
+		await rm(root, { recursive: true, force: true });
+	}
+});
+
+test("uninitialized project bounces to built-in tools when declined", async () => {
+	const root = await mkdtemp(join(tmpdir(), "my-pi-codegraph-"));
+	const { exec, calls } = mockExec(() => ({ stdout: "unreachable" }));
+	const { handle } = makeHandler(exec);
+	try {
+		const result = await handle({ query: "auth" }, mockCtx(root, async () => false));
+		assert.match(result.content[0].text ?? "", /find\/grep\/read\/LSP/);
+		assert.equal(calls.length, 0, "declined init must not spawn the CLI at all");
+	} finally {
+		await rm(root, { recursive: true, force: true });
+	}
+});
+
+test("concurrent calls on an uninitialized project share one init decision", async () => {
+	const root = await mkdtemp(join(tmpdir(), "my-pi-codegraph-"));
+	let confirmCalls = 0;
+	const { exec, calls } = mockExec(() => ({ stdout: "ok" }));
+	const pending = new Map<string, Promise<string | undefined>>();
+	const handle = createCodegraphExploreHandler(exec, new Map(), pending);
+	try {
+		const [a, b] = await Promise.all([
+			handle({ query: "one" }, mockCtx(root, async () => {
+				confirmCalls += 1;
+				return true;
+			})),
+			handle({ query: "two" }, mockCtx(root, async () => {
+				confirmCalls += 1;
+				return true;
+			})),
+		]);
+		assert.equal(a.content[0].text, "ok");
+		assert.equal(b.content[0].text, "ok");
+		assert.equal(confirmCalls, 1, "parallel callers must not double-prompt");
+		assert.equal(
+			calls.filter(({ args }) => args[0] === "init").length,
+			1,
+			"parallel callers must share a single init",
+		);
+	} finally {
+		await rm(root, { recursive: true, force: true });
+	}
+});
+
+test("init failure is reported instead of exploring", async () => {
+	const root = await mkdtemp(join(tmpdir(), "my-pi-codegraph-"));
+	const { exec } = mockExec((_command, args) =>
+		args[0] === "init" ? { code: 1, stderr: "boom" } : { stdout: "unreachable" },
+	);
+	const { handle } = makeHandler(exec);
+	try {
+		const result = await handle({ query: "auth" }, mockCtx(root, async () => true));
+		assert.match(result.content[0].text ?? "", /codegraph init 失败/);
+	} finally {
+		await rm(root, { recursive: true, force: true });
+	}
+});
+
+test("missing CLI surfaces an install hint instead of throwing", async () => {
+	const { root, cleanup } = await makeIndexedProject();
+	const exec: CodegraphExec = async () => {
+		throw new Error("spawn codegraph ENOENT");
+	};
+	const { handle } = makeHandler(exec);
+	try {
+		const result = await handle({ query: "auth" }, mockCtx(root));
+		assert.match(result.content[0].text ?? "", /无法执行 codegraph CLI/);
+	} finally {
+		await cleanup();
+	}
+});
+
+test("projectPath overrides the session cwd", async () => {
+	const { root, cleanup } = await makeIndexedProject();
+	const other = await mkdtemp(join(tmpdir(), "my-pi-codegraph-"));
+	const { exec, calls } = mockExec(() => ({ stdout: "ok" }));
+	const { handle } = makeHandler(exec);
+	try {
+		const params: ExploreParams = { query: "auth", projectPath: root };
+		await handle(params, mockCtx(other));
+		assert.deepEqual(calls[0].args, ["explore", "-p", root, "auth"]);
+	} finally {
+		await cleanup();
+		await rm(other, { recursive: true, force: true });
+	}
+});