feat(profiles): refactor profiles to centralize logic in core

Centralized profile loading and management in packages/core.
Updated CLI commands to use core ProfileManager.
Implemented persistent profile selection in loadCliConfig.
Standardized profile format as Markdown with YAML frontmatter.
Verified multi-extension loading with 'coder' profile.

packages/core/src/profiles/profileManager.test.ts

@@ -0,0 +1,98 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
+import * as fs from 'node:fs/promises';
+import * as os from 'node:os';
+import * as path from 'node:path';
+import { ProfileManager } from './profileManager.js';
+import { coreEvents } from '../utils/events.js';
+
+describe('ProfileManager', () => {
+  let testProfilesDir: string;
+  let profileManager: ProfileManager;
+
+  beforeEach(async () => {
+    testProfilesDir = await fs.mkdtemp(
+      path.join(os.tmpdir(), 'profile-manager-test-'),
+    );
+    profileManager = new ProfileManager(testProfilesDir);
+    vi.spyOn(coreEvents, 'emitFeedback');
+  });
+
+  afterEach(async () => {
+    await fs.rm(testProfilesDir, { recursive: true, force: true });
+    vi.restoreAllMocks();
+  });
+
+  it('should load profiles from directory', async () => {
+    await fs.writeFile(
+      path.join(testProfilesDir, 'test.md'),
+      '---\nname: test\n---\nBody',
+    );
+    await profileManager.load();
+    const profiles = profileManager.getAllProfiles();
+    expect(profiles).toHaveLength(1);
+    expect(profiles[0].name).toBe('test');
+  });
+
+  it('should manage active profile', async () => {
+    await fs.writeFile(
+      path.join(testProfilesDir, 'my-profile.md'),
+      '---\nname: my-profile\n---\nBody',
+    );
+    await profileManager.load();
+    profileManager.setActiveProfile('my-profile');
+    expect(profileManager.getActiveProfileName()).toBe('my-profile');
+  });
+
+  it('should install profile by copying', async () => {
+    const sourceDir = await fs.mkdtemp(
+      path.join(os.tmpdir(), 'source-profile-'),
+    );
+    const sourceFile = path.join(sourceDir, 'new-profile.md');
+    await fs.writeFile(sourceFile, '---\nname: new-profile\n---\nNew Body');
+
+    const installed = await profileManager.installProfile(sourceFile);
+    expect(installed).toBeDefined();
+    expect(installed.name).toBe('new-profile');
+    expect(installed.location).toBe(
+      path.join(testProfilesDir, 'new-profile.md'),
+    );
+
+    const profiles = profileManager.getAllProfiles();
+    expect(profiles.find((p) => p.name === 'new-profile')).toBeDefined();
+  });
+
+  it('should link profile using symlink', async () => {
+    const sourceDir = await fs.mkdtemp(path.join(os.tmpdir(), 'source-link-'));
+    const sourceFile = path.join(sourceDir, 'linked-profile.md');
+    await fs.writeFile(
+      sourceFile,
+      '---\nname: linked-profile\n---\nLinked Body',
+    );
+
+    const linked = await profileManager.linkProfile(sourceFile);
+    expect(linked).toBeDefined();
+    expect(linked.name).toBe('linked-profile');
+
+    const targetPath = path.join(testProfilesDir, 'linked-profile.md');
+    const stats = await fs.lstat(targetPath);
+    expect(stats.isSymbolicLink()).toBe(true);
+  });
+
+  it('should reload profiles', async () => {
+    await profileManager.load();
+    expect(profileManager.getAllProfiles()).toHaveLength(0);
+
+    await fs.writeFile(
+      path.join(testProfilesDir, 'test.md'),
+      '---\nname: test\n---\nBody',
+    );
+    await profileManager.load();
+    expect(profileManager.getAllProfiles()).toHaveLength(1);
+  });
+});