feat: add Docker support and Gitea publish workflow

- Add a multi-stage Dockerfile for building and running the Go backend
- Add .dockerignore to optimize the Docker build context
- Create a Gitea Actions workflow to build and publish Docker images on tag push
- Register a new `/health` endpoint for container healthchecks
- Update README.md with Docker and Podman deployment instructions
- Ignore local `docker-compose.yml` in .gitignore

.dockerignore

@@ -0,0 +1,23 @@
+.git
+.gitea
+.github
+.idea
+.vscode
+
+data
+backend/warpbox
+warpbox
+
+.env
+scripts/env/*.env
+!scripts/env/*.env.example
+
+*.log
+*.tmp
+*.swp
+.DS_Store
+
+docs/Mock-Up/Mockup Magic/node_modules
+docs/Mock-Up/Mockup Magic/.tanstack
+docs/Mock-Up/Mockup Magic/dist
+docs/Mock-Up/Mockup Magic/.wrangler