feat: integrate AbstractWizard for initialization

- Add wizard service (git.hangman-lab.top/hzhang/abstract-wizard:latest)
- Add wizard-init service: uploads init-config on first deploy
- Backend reads wizard config on startup, creates admin user + default project
- Add init-config/harborforge.json with default admin credentials
- Update README with initialization docs
- Startup order: mysql → wizard → wizard-init → backend → frontend

.env.example

@@ -10,6 +10,10 @@ SECRET_KEY=change_me_in_production
 LOG_LEVEL=INFO
 BACKEND_PORT=8000
 
+# AbstractWizard
+WIZARD_URL=http://wizard:8080
+WIZARD_CONFIG=harborforge.json
+
 # Frontend
 FRONTEND_PORT=3000
 VITE_API_BASE=/api