feat(cli): add version, indexPath, lastIndexed to status --json (#329)

Adds `version`, `indexPath`, and an ISO `lastIndexed` to `codegraph status --json`, plus a `CodeGraph.getLastIndexedAt()` library method. `agentCount` dropped (no clear consumer). Reworked from contributor PRs #333 and #480.

Co-Authored-By: Javier Gómez <199902626+12122J@users.noreply.github.com>
Co-Authored-By: Ran <8403607+eddieran@users.noreply.github.com>
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

__tests__/status-json.test.ts

@@ -0,0 +1,89 @@
+/**
+ * Tests for the CI/scripting fields `codegraph status --json` exposes (issue
+ * #329): the `version`, `indexPath`, and `lastIndexed` fields, plus the
+ * matching `CodeGraph.getLastIndexedAt()` library method.
+ *
+ * The CLI itself is exercised end-to-end against the built binary so the JSON
+ * field names survive future refactors of the underlying plumbing.
+ */
+
+import { describe, it, expect, beforeEach, afterEach } from 'vitest';
+import { execFileSync } from 'child_process';
+import * as fs from 'fs';
+import * as path from 'path';
+import * as os from 'os';
+import { CodeGraph } from '../src';
+
+const BIN = path.resolve(__dirname, '../dist/bin/codegraph.js');
+const PKG_VERSION = JSON.parse(
+  fs.readFileSync(path.resolve(__dirname, '../package.json'), 'utf-8'),
+).version as string;
+
+function runStatusJson(cwd: string): Record<string, unknown> {
+  const stdout = execFileSync(process.execPath, [BIN, 'status', '--json'], {
+    cwd,
+    encoding: 'utf-8',
+    env: { ...process.env, CODEGRAPH_NO_DAEMON: '1' },
+    stdio: ['ignore', 'pipe', 'pipe'],
+  });
+  // JSON mode prints exactly one line to stdout; be defensive about any stray
+  // leading output by parsing the last non-empty line.
+  const line = stdout.trim().split('\n').filter(Boolean).pop()!;
+  return JSON.parse(line);
+}
+
+describe('codegraph status --json — CI fields (#329)', () => {
+  let tempDir: string;
+
+  beforeEach(() => {
+    tempDir = fs.mkdtempSync(path.join(os.tmpdir(), 'codegraph-status-json-'));
+  });
+  afterEach(() => {
+    fs.rmSync(tempDir, { recursive: true, force: true });
+  });
+
+  it('getLastIndexedAt() is null before indexing and a recent ms timestamp after', async () => {
+    const cg = CodeGraph.initSync(tempDir);
+    expect(cg.getLastIndexedAt()).toBeNull();
+
+    fs.writeFileSync(path.join(tempDir, 'a.ts'), 'export const x = 1;\n');
+    const before = Date.now();
+    await cg.indexAll();
+    const after = Date.now();
+
+    const last = cg.getLastIndexedAt();
+    expect(last).not.toBeNull();
+    expect(typeof last).toBe('number');
+    expect(last!).toBeGreaterThanOrEqual(before - 1000);
+    expect(last!).toBeLessThanOrEqual(after + 1000);
+    cg.close();
+  });
+
+  it('status --json on an UNINITIALIZED project reports version + indexPath + lastIndexed:null', () => {
+    const out = runStatusJson(tempDir);
+    expect(out.initialized).toBe(false);
+    expect(out.version).toBe(PKG_VERSION);
+    expect(typeof out.indexPath).toBe('string');
+    expect(out.indexPath as string).toContain('.codegraph');
+    expect(out.lastIndexed).toBeNull();
+  });
+
+  it('status --json on an INDEXED project reports version + indexPath + a round-trippable lastIndexed', async () => {
+    fs.writeFileSync(path.join(tempDir, 'a.ts'), 'export const x = 1;\n');
+    const before = Date.now();
+    const cg = CodeGraph.initSync(tempDir);
+    await cg.indexAll();
+    const after = Date.now();
+    cg.close();
+
+    const out = runStatusJson(tempDir);
+    expect(out.initialized).toBe(true);
+    expect(out.version).toBe(PKG_VERSION);
+    expect(out.indexPath as string).toContain('.codegraph');
+    expect(typeof out.lastIndexed).toBe('string');
+    // ISO string that round-trips back into the index window.
+    const ms = Date.parse(out.lastIndexed as string);
+    expect(ms).toBeGreaterThanOrEqual(before - 1000);
+    expect(ms).toBeLessThanOrEqual(after + 1000);
+  });
+});