feat: Initial commit - Train tracking system

Complete real-time train tracking system for Spanish railways (Renfe/Cercanías):

- Backend API (Node.js/Express) with GTFS-RT polling workers
- Frontend dashboard (React/Vite) with Leaflet maps
- Real-time updates via Socket.io WebSocket
- PostgreSQL/PostGIS database with Flyway migrations
- Redis caching layer
- Docker Compose configuration for development and production
- Gitea CI/CD workflows (lint, auto-tag, release)
- Production deployment with nginx + Let's Encrypt SSL

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

.gitea/workflows/release.yml

@@ -0,0 +1,76 @@
+name: Release - Build and Publish Docker Images
+
+on:
+  push:
+    tags:
+      - 'v*.*.*'
+
+jobs:
+  build-and-publish:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Extract version from tag
+        id: version
+        run: |
+          VERSION=${GITHUB_REF#refs/tags/v}
+          echo "version=$VERSION" >> $GITHUB_OUTPUT
+          echo "Building version: $VERSION"
+
+      - name: Get current date
+        id: date
+        run: echo "date=$(date -u +'%Y-%m-%dT%H:%M:%SZ')" >> $GITHUB_OUTPUT
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Login to Gitea Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ secrets.REGISTRY_URL }}
+          username: ${{ secrets.REGISTRY_USERNAME }}
+          password: ${{ secrets.REGISTRY_PASSWORD }}
+
+      - name: Build and push backend image
+        uses: docker/build-push-action@v5
+        with:
+          context: ./backend
+          push: true
+          build-args: |
+            APP_VERSION=${{ steps.version.outputs.version }}
+            BUILD_DATE=${{ steps.date.outputs.date }}
+            GIT_COMMIT=${{ github.sha }}
+          tags: |
+            ${{ secrets.REGISTRY_URL }}/trenes/backend:${{ steps.version.outputs.version }}
+            ${{ secrets.REGISTRY_URL }}/trenes/backend:latest
+          provenance: false
+          sbom: false
+
+      - name: Build and push frontend image
+        uses: docker/build-push-action@v5
+        with:
+          context: ./frontend
+          push: true
+          build-args: |
+            VITE_API_URL=${{ secrets.PROD_API_URL }}
+            VITE_WS_URL=${{ secrets.PROD_WS_URL }}
+            APP_VERSION=${{ steps.version.outputs.version }}
+            BUILD_DATE=${{ steps.date.outputs.date }}
+            GIT_COMMIT=${{ github.sha }}
+          tags: |
+            ${{ secrets.REGISTRY_URL }}/trenes/frontend:${{ steps.version.outputs.version }}
+            ${{ secrets.REGISTRY_URL }}/trenes/frontend:latest
+          provenance: false
+          sbom: false
+
+      - name: Summary
+        run: |
+          echo "### Docker Images Published 🐳" >> $GITHUB_STEP_SUMMARY
+          echo "" >> $GITHUB_STEP_SUMMARY
+          echo "**Version:** ${{ steps.version.outputs.version }}" >> $GITHUB_STEP_SUMMARY
+          echo "" >> $GITHUB_STEP_SUMMARY
+          echo "**Images:**" >> $GITHUB_STEP_SUMMARY
+          echo "- \`${{ secrets.REGISTRY_URL }}/trenes/backend:${{ steps.version.outputs.version }}\`" >> $GITHUB_STEP_SUMMARY
+          echo "- \`${{ secrets.REGISTRY_URL }}/trenes/frontend:${{ steps.version.outputs.version }}\`" >> $GITHUB_STEP_SUMMARY