feat(cli): add gemini-auth command and alias support

src/cli/gemini-auth.test.ts

@@ -0,0 +1,80 @@
+import { Command } from 'commander';
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+
+const { mockLoadStoredGeminiAuth, mockStoreGeminiAuth } = vi.hoisted(() => ({
+  mockLoadStoredGeminiAuth: vi.fn(),
+  mockStoreGeminiAuth: vi.fn(),
+}));
+
+const { mockCreateInterface } = vi.hoisted(() => ({
+  mockCreateInterface: vi.fn(),
+}));
+
+vi.mock('../auth/index.js', () => ({
+  loadStoredGeminiAuth: mockLoadStoredGeminiAuth,
+  storeGeminiAuth: mockStoreGeminiAuth,
+}));
+
+vi.mock('readline', () => ({
+  default: {
+    createInterface: mockCreateInterface,
+  },
+}));
+
+function mockReadlineAnswers(answers: string[]): void {
+  const queue = [...answers];
+  mockCreateInterface.mockImplementation(() => ({
+    question: (_prompt: string, cb: (answer: string) => void) => cb(queue.shift() ?? ''),
+    close: () => undefined,
+  }));
+}
+
+describe('gemini-auth command', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    mockLoadStoredGeminiAuth.mockReset();
+    mockStoreGeminiAuth.mockReset();
+    mockCreateInterface.mockReset();
+  });
+
+  it('cancels when key exists and user answers no', async () => {
+    mockLoadStoredGeminiAuth.mockReturnValue({ api_key: 'gem-existing', created_at: '2026-02-21T00:00:00.000Z' });
+    mockReadlineAnswers(['n']);
+
+    const program = new Command();
+    const { registerGeminiAuthCommand } = await import('./gemini-auth.js');
+    registerGeminiAuthCommand(program);
+
+    const consoleLog = vi.spyOn(console, 'log').mockImplementation(() => undefined);
+    const exitSpy = vi.spyOn(process, 'exit').mockImplementation(((code?: number) => {
+      throw new Error(`EXIT:${code ?? 0}`);
+    }) as never);
+
+    await expect(program.parseAsync(['node', 'test', 'gemini-auth'])).rejects.toThrow('EXIT:0');
+    expect(mockStoreGeminiAuth).not.toHaveBeenCalled();
+    expect(consoleLog).toHaveBeenCalledWith('Cancelled.');
+
+    exitSpy.mockRestore();
+    consoleLog.mockRestore();
+  });
+
+  it('stores a new key when user confirms re-authentication', async () => {
+    mockLoadStoredGeminiAuth.mockReturnValue({ api_key: 'gem-existing', created_at: '2026-02-21T00:00:00.000Z' });
+    mockReadlineAnswers(['y', 'gem-new']);
+
+    const program = new Command();
+    const { registerGeminiAuthCommand } = await import('./gemini-auth.js');
+    registerGeminiAuthCommand(program);
+
+    const consoleLog = vi.spyOn(console, 'log').mockImplementation(() => undefined);
+    const consoleError = vi.spyOn(console, 'error').mockImplementation(() => undefined);
+
+    await program.parseAsync(['node', 'test', 'gemini-auth']);
+
+    expect(mockStoreGeminiAuth).toHaveBeenCalledWith('gem-new');
+    expect(consoleError).not.toHaveBeenCalled();
+
+    consoleLog.mockRestore();
+    consoleError.mockRestore();
+  });
+});