test: add unit and integration test suite

Add 34 tests (27 unit, 7 integration) using node:test runner:

Unit tests:
- pickServer(), findRoot(), pathToUri(), uriToPath()
- isLspCommand(), listCommands()
- formatHover(), formatDefinition(), formatReferences(), formatDiagnostics()

Integration tests:
- daemon lifecycle (status/stop) on isolated socket
- CLI --no-daemon queries (hover, documentSymbol, diagnostics)

Supporting changes:
- socketPath() honors PI_LSP_SOCKET_PATH env var for test isolation
- test fixtures for valid and broken TypeScript files
- npm test / test:unit / test:integration scripts

test/integration/cli-daemon.test.ts

@@ -0,0 +1,76 @@
+// Daemon Lifecycle Tests — daemon status, stop, shutdown via CLI.
+// Uses an isolated socket (PI_LSP_SOCKET_PATH) so it never touches a real session daemon.
+import { describe, it, before, after } from "node:test";
+import * as assert from "node:assert/strict";
+import {
+  setTestSocket,
+  stopTestDaemon,
+  runCli,
+} from "../helpers.ts";
+
+describe("cli daemon lifecycle", () => {
+  // Isolated Environment — each test suite gets its own socket path.
+  const env = { ...process.env };
+  let cleanup: () => void;
+
+  before(() => {
+    cleanup = setTestSocket(env);
+    // Stop any stale daemon on this socket before tests run.
+    stopTestDaemon(env);
+  });
+
+  after(() => {
+    // Tear down daemon and clean up socket after all tests.
+    stopTestDaemon(env);
+    cleanup();
+  });
+
+  it("daemon stop works when no daemon is running", async () => {
+    const { stderr } = await runCli(["daemon", "stop"], env);
+    // When no daemon is running, stderr should mention "not running" or similar.
+    // We just assert it doesn't crash.
+    assert.ok(
+      stderr.includes("not running") || stderr === "",
+      `Expected clean stop, got: ${stderr}`,
+    );
+  });
+
+  it("daemon status works after autospawn", async () => {
+    // First request autospawns the daemon; status should show it.
+    const { stdout } = await runCli(["daemon", "status"], env);
+    const result = JSON.parse(stdout);
+    assert.ok(
+      typeof result === "object" && result !== null,
+      "Status should return an object",
+    );
+    // Status returns a servers array (may be empty if no files queried yet).
+    assert.ok(
+      !("error" in result) || result.error === undefined,
+      "Status should not have an error field",
+    );
+  });
+
+  it("daemon stop shuts down the daemon", async () => {
+    // Ensure daemon is running first.
+    await runCli(["daemon", "status"], env);
+
+    // Stop it.
+    const { stdout } = await runCli(["daemon", "stop"], env);
+    const result = JSON.parse(stdout);
+    assert.ok(
+      typeof result === "object" && result !== null,
+      "Stop should return an object",
+    );
+  });
+
+  it("daemon status after stop shows no servers", async () => {
+    // After stop, the daemon is gone. A new status call will autospawn a fresh
+    // daemon with no cached servers.
+    const { stdout } = await runCli(["daemon", "status"], env);
+    const result = JSON.parse(stdout);
+    assert.ok(
+      typeof result === "object" && result !== null,
+      "Status should return an object after restart",
+    );
+  });
+});