feat(root): scaffold Django project with djinit

Add initial project skeleton using djinit to enable rapid development, CI integration, and deployment setup.

New Features
- Create .djinit with unified project structure and Tailwind/HTMX enabled.
- Add .env.sample with default Django, database, and frontend URLs.
- Generate comprehensive .gitignore covering Python, Django, OS, and secret files.
- Provide Procfile for Gunicorn web process and release migrations.
- Scaffold README.md with project overview and features.
- Add manage.py enhanced with environ for .env support.
- Initialize pyproject.toml with modern metadata and ruff linting config.
- Add requirements.txt mirroring dependencies.
- Include runtime.txt pinning Python 3.13.
- Update uv.lock to lock dependency versions.

Enhancements
- Upgrade to latest Django 6.0.5 and DRF ecosystem.
- Configure ruff with line-length 88 and isort settings.
- Use gunicorn with optimal worker configuration.
- Include dj-database-url and psycopg binary for robust PostgreSQL connectivity.

Bug Fixes
- None.

.env.sample

@@ -0,0 +1,19 @@
+# Django settings
+DJANGO_SETTINGS_MODULE=core.settings.development
+SECRET_KEY=your-secret-key
+ALLOWED_HOSTS=api.your-domain.com,www.your-domain.com
+
+# Database URL (recommended for production)
+DATABASE_URL=postgres://user:password@localhost:5432/core
+
+# Frontend URL
+FRONTEND_URL=https://frontend.your-domain.com,www.frontend.your-domain.com
+
+# Email settings
+EMAIL_HOST=
+EMAIL_PORT=
+EMAIL_USE_TLS=
+EMAIL_HOST_USER=
+EMAIL_HOST_PASSWORD=
+DEFAULT_FROM_EMAIL=
+SERVER_EMAIL=