Add CMS features with admin interface and OAuth authentication integration

- Introduced Caddy server for serving frontend and API backend.
- Implemented admin dashboard for creating, editing, and managing events.
- Replaced session-based authentication with token-based OAuth using Gitea.
- Added support for drag-and-drop event reordering in the admin interface.
- Standardized Fastify route validation with JSON schemas.
- Enhanced authentication flow with cookie-based state and secure token storage.
- Reworked backend routes to handle publishing, event management, and content updates.
- Updated `Dockerfile.caddy` and `fly.toml` for deployment configuration.

backend/.env.local

@@ -0,0 +1,34 @@
+# Local development environment for Gallus CMS Backend
+
+# Database
+DB_CLIENT=sqlite
+DATABASE_URL=
+DATABASE_PATH=./data/gallus_cms.db
+
+# Gitea OAuth
+GITEA_URL=https://git.bookageek.ch
+GITEA_CLIENT_ID=bcddfe24-3099-41bc-bb7a-6c6d80bd9048
+GITEA_CLIENT_SECRET=gto_me7hsswrsdq2ygey65edlc6qa2xxr3i5nrq7q4jvjwx654ytrh7q
+# Frontend proxy callback in local dev
+GITEA_REDIRECT_URI=http://localhost:4321/api/auth/callback
+GITEA_ALLOWED_USERS=Gallus-maintanance
+
+# Git repository for content versioning
+GIT_REPO_URL=https://git.bookageek.ch/Kenzo/Gallus_Pub
+GIT_TOKEN=1482ae7bcdbd7610bf0cfd468b6757722d16a2a2
+GIT_USER_NAME=Gallus-maintanance
+GIT_USER_EMAIL=Admin@gallus-pub.ch
+GIT_WORKSPACE_DIR=./data/workspace
+
+# JWT & Session secrets (use strong random strings in real deployments)
+JWT_SECRET=local-dev-jwt-secret-please-change-1234567890abcdef
+SESSION_SECRET=local-dev-session-secret-please-change-abcdef1234567890
+
+# Server & CORS
+PORT=3000
+NODE_ENV=development
+FRONTEND_URL=http://localhost:4321
+CORS_ORIGIN=http://localhost:4321
+
+# Upload limits
+MAX_FILE_SIZE=5242880