Wire frontend into Docker Compose with type-safe API client

- Add frontend service to docker-compose.yml (port 3000, BACKEND_URL env var)
- Add frontend/Dockerfile using adapter-node for plain Node/Docker runtime
- Switch svelte.config.js from adapter-auto to adapter-node
- Generate OpenAPI types from backend spec (openapi-typescript + openapi-fetch)
- Add src/lib/server/api.ts as server-only typed API client factory
- Add generate:api script to regenerate types when backend spec changes

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/Dockerfile

@@ -0,0 +1,15 @@
+FROM node:22-alpine AS build
+WORKDIR /app
+COPY package*.json ./
+RUN npm ci
+COPY . .
+RUN npm run build
+
+FROM node:22-alpine
+WORKDIR /app
+COPY --from=build /app/build build/
+COPY --from=build /app/node_modules node_modules/
+COPY package.json .
+EXPOSE 3000
+ENV NODE_ENV=production
+CMD ["node", "build"]