Initial commit: BOM Local Radar Card

- Custom Home Assistant card for displaying BOM radar data
- Docker-based build system (no local Node.js required)
- Test environment with Home Assistant and BOM service
- TypeScript source with LitElement framework
- HACS integration ready

Dockerfile.build

@@ -0,0 +1,22 @@
+# Dockerfile for building the BOM Local Radar Card
+# This isolates Node.js/npm in a container for security
+FROM node:20-alpine
+
+WORKDIR /build
+
+# Copy package files first for better caching
+COPY package*.json ./
+COPY tsconfig.json ./
+COPY rollup.config.js ./
+
+# Install dependencies (including devDependencies)
+# Use npm install since we may have updated package.json
+RUN npm install
+
+# Copy source files
+COPY src/ ./src/
+
+# Default command: run the build
+# This ensures the build runs when the container starts, not during image creation
+CMD ["npm", "run", "build"]
+