Migrate setup from bash scripts to cross-platform Node.js modules (#382)

* refactor: migrate setup from bash scripts to cross-platform Node.js modules

Replace 9 bash scripts + qr-auth.html with a two-phase setup system:
a bash bootstrap (setup.sh) for Node.js/npm verification, and TypeScript
modules (src/setup/) for everything else. Resolves cross-platform issues:
sed -i replaced with fs operations, sqlite3 CLI replaced with better-sqlite3,
browser opening made cross-platform, service management supports launchd/
systemd/WSL nohup fallback, SQL injection prevented with parameterized queries.

Add Linux systemctl equivalents alongside macOS launchctl commands in 8 skill
files and CLAUDE.md.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: setup migration issues — pairing code, systemd fallback, nohup escaping

- Emit WhatsApp pairing code immediately when received, before polling
  for auth completion. Previously the code was only shown in the final
  status block after auth succeeded — a catch-22 since the user needs
  the code to authenticate. (whatsapp-auth.ts)

- Add systemd user session pre-check before attempting to write the
  user-level service unit. Falls back to nohup wrapper when user-level
  systemd is unavailable (e.g. su session without login/D-Bus). (service.ts)

- Rewrite nohup wrapper template using array join instead of template
  literal to fix shell variable escaping (\\$ → $). (service.ts)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: detect stale docker group and kill
  orphaned processes on Linux systemd

* fix: remove redundant shell option from execSync to fix TS2769

execSync already runs in a shell by default; the explicit `shell: true`
caused a type error with @types/node which expects string, not boolean.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* feat: hide QR browser auth option on headless Linux

Emit IS_HEADLESS from environment step and condition SKILL.md to
only show pairing code + QR terminal when no display server is
available (headless Linux without WSL). WSL is excluded from the
headless gate because browser opening works via Windows interop.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

src/setup/platform.test.ts

@@ -0,0 +1,121 @@
+import { describe, it, expect } from 'vitest';
+
+import {
+  getPlatform,
+  isWSL,
+  isRoot,
+  isHeadless,
+  hasSystemd,
+  getServiceManager,
+  commandExists,
+  getNodeVersion,
+  getNodeMajorVersion,
+} from './platform.js';
+
+// --- getPlatform ---
+
+describe('getPlatform', () => {
+  it('returns a valid platform string', () => {
+    const result = getPlatform();
+    expect(['macos', 'linux', 'unknown']).toContain(result);
+  });
+
+  it('returns linux on this system', () => {
+    // This test runs on Linux
+    expect(getPlatform()).toBe('linux');
+  });
+});
+
+// --- isWSL ---
+
+describe('isWSL', () => {
+  it('returns a boolean', () => {
+    expect(typeof isWSL()).toBe('boolean');
+  });
+
+  it('checks /proc/version for WSL markers', () => {
+    // On non-WSL Linux, should return false
+    // On WSL, should return true
+    // Just verify it doesn't throw
+    const result = isWSL();
+    expect(typeof result).toBe('boolean');
+  });
+});
+
+// --- isRoot ---
+
+describe('isRoot', () => {
+  it('returns a boolean', () => {
+    expect(typeof isRoot()).toBe('boolean');
+  });
+});
+
+// --- isHeadless ---
+
+describe('isHeadless', () => {
+  it('returns a boolean', () => {
+    expect(typeof isHeadless()).toBe('boolean');
+  });
+});
+
+// --- hasSystemd ---
+
+describe('hasSystemd', () => {
+  it('returns a boolean', () => {
+    expect(typeof hasSystemd()).toBe('boolean');
+  });
+
+  it('checks /proc/1/comm', () => {
+    // On systemd systems, should return true
+    // Just verify it doesn't throw
+    const result = hasSystemd();
+    expect(typeof result).toBe('boolean');
+  });
+});
+
+// --- getServiceManager ---
+
+describe('getServiceManager', () => {
+  it('returns a valid service manager', () => {
+    const result = getServiceManager();
+    expect(['launchd', 'systemd', 'none']).toContain(result);
+  });
+
+  it('returns systemd or none on Linux', () => {
+    const result = getServiceManager();
+    // On Linux, should be systemd if available, else none
+    expect(['systemd', 'none']).toContain(result);
+  });
+});
+
+// --- commandExists ---
+
+describe('commandExists', () => {
+  it('returns true for node', () => {
+    expect(commandExists('node')).toBe(true);
+  });
+
+  it('returns false for nonexistent command', () => {
+    expect(commandExists('this_command_does_not_exist_xyz_123')).toBe(false);
+  });
+});
+
+// --- getNodeVersion ---
+
+describe('getNodeVersion', () => {
+  it('returns a version string', () => {
+    const version = getNodeVersion();
+    expect(version).not.toBeNull();
+    expect(version).toMatch(/^\d+\.\d+\.\d+/);
+  });
+});
+
+// --- getNodeMajorVersion ---
+
+describe('getNodeMajorVersion', () => {
+  it('returns at least 20', () => {
+    const major = getNodeMajorVersion();
+    expect(major).not.toBeNull();
+    expect(major!).toBeGreaterThanOrEqual(20);
+  });
+});