Initial commit: Price Hunter — self-hosted price comparison engine

Complete application scaffolding with:
- Backend: Node.js + Fastify + sql.js (SQLite)
- Frontend: SvelteKit + Tailwind CSS
- Scraper engine with parallel fan-out, rate limiting, cheerio-based parsing
- Store management with CSS selector config and per-store test pages
- Docker setup for single-command deployment

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Dockerfile

@@ -0,0 +1,36 @@
+# Stage 1: Build client
+FROM node:20-alpine AS client-build
+WORKDIR /app/src/client
+COPY src/client/package*.json ./
+RUN npm ci
+COPY src/client/ ./
+RUN npm run build
+
+# Stage 2: Build server
+FROM node:20-alpine AS server-build
+WORKDIR /app
+COPY package*.json ./
+RUN npm ci
+COPY tsconfig.json ./
+COPY src/server/ ./src/server/
+RUN npx tsc
+
+# Stage 3: Production runtime
+FROM node:20-alpine
+WORKDIR /app
+
+COPY package*.json ./
+RUN npm ci --omit=dev
+
+COPY --from=server-build /app/dist ./dist
+COPY --from=client-build /app/src/client/build ./dist/client
+COPY src/server/db/migrations ./dist/server/db/migrations
+
+ENV NODE_ENV=production
+ENV PORT=3000
+ENV DATABASE_PATH=/app/data/pricehunter.db
+
+EXPOSE 3000
+VOLUME /app/data
+
+CMD ["node", "dist/server/index.js"]