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

backend/libs/handlers/health_test.go

@@ -0,0 +1,28 @@
+package handlers
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestHealthRoutes(t *testing.T) {
+	app, cleanup := newTestApp(t)
+	defer cleanup()
+
+	mux := http.NewServeMux()
+	app.RegisterRoutes(mux)
+
+	for _, path := range []string{"/health", "/healthz", "/api/v1/health"} {
+		t.Run(path, func(t *testing.T) {
+			request := httptest.NewRequest(http.MethodGet, path, nil)
+			response := httptest.NewRecorder()
+
+			mux.ServeHTTP(response, request)
+
+			if response.Code != http.StatusOK {
+				t.Fatalf("status = %d, body = %s", response.Code, response.Body.String())
+			}
+		})
+	}
+}