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>

.claude/skills/debug/SKILL.md

@@ -43,9 +43,11 @@ Set `LOG_LEVEL=debug` for verbose output:
 # For development
 LOG_LEVEL=debug npm run dev
 
-# For launchd service, add to plist EnvironmentVariables:
+# For launchd service (macOS), add to plist EnvironmentVariables:
 <key>LOG_LEVEL</key>
 <string>debug</string>
+# For systemd service (Linux), add to unit [Service] section:
+# Environment=LOG_LEVEL=debug
 ```
 
 Debug level shows: