feat: Docker deployment + Gitea CI/CD workflow

- Multi-stage Dockerfile: Node frontend build → Python wheel build → slim runtime
- Backend serves SvelteKit static output via FastAPI StaticFiles mount
- docker-compose.yml with named volume for /data persistence
- Gitea Actions workflow: build/push Docker image + create release on v* tags
- Add NOTIFY_BRIDGE_STATIC_DIR config for frontend path
- Fix run() to use configurable host/port

Dockerfile

@@ -0,0 +1,65 @@
+# =============================================================================
+# Stage 1: Build frontend (SvelteKit static output)
+# =============================================================================
+FROM node:22-alpine AS frontend-build
+
+WORKDIR /build
+
+# Cache npm install layer
+COPY frontend/package.json frontend/package-lock.json ./
+RUN npm ci
+
+# Build static site
+COPY frontend/ ./
+RUN npm run build
+
+# =============================================================================
+# Stage 2: Build Python wheels
+# =============================================================================
+FROM python:3.12-slim AS python-build
+
+WORKDIR /build
+
+RUN pip install --no-cache-dir build
+
+# Build core package wheel
+COPY packages/core/ packages/core/
+RUN python -m build packages/core/ --wheel --outdir /wheels
+
+# Build server package wheel
+COPY packages/server/ packages/server/
+RUN python -m build packages/server/ --wheel --outdir /wheels
+
+# =============================================================================
+# Stage 3: Runtime
+# =============================================================================
+FROM python:3.12-slim
+
+WORKDIR /app
+
+# Install wheels
+COPY --from=python-build /wheels/ /tmp/wheels/
+RUN pip install --no-cache-dir /tmp/wheels/*.whl && rm -rf /tmp/wheels
+
+# Copy frontend build
+COPY --from=frontend-build /build/build/ /app/static/
+
+# Create non-root user and data directory
+RUN useradd --create-home --shell /bin/bash appuser \
+    && mkdir -p /data \
+    && chown appuser:appuser /data
+
+# Environment defaults
+ENV NOTIFY_BRIDGE_DATA_DIR=/data \
+    NOTIFY_BRIDGE_STATIC_DIR=/app/static \
+    NOTIFY_BRIDGE_DEBUG=false
+
+VOLUME /data
+EXPOSE 8420
+
+USER appuser
+
+HEALTHCHECK --interval=30s --timeout=5s --retries=3 --start-period=10s \
+    CMD python -c "import urllib.request; urllib.request.urlopen('http://localhost:8420/api/health')"
+
+CMD ["notify-bridge"]