feat: full-stack frontend with gateway API integration

- Dashboard with real-time service health, screening results, stream stats
- Stock list page with search, market filter, pagination via KIS API
- Stock detail page with prices, valuation, AI analysis, catalysts
- Screening page with trigger + results display
- Pipeline monitoring with service status and stream info
- Typed API client (lib/api.ts) for all gateway endpoints
- Reusable components (Sidebar, StatCard)
- Dockerfile with build-time NEXT_PUBLIC_API_URL injection
- Docker-compatible .dockerignore

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

Dockerfile

@@ -0,0 +1,21 @@
+FROM node:20-alpine AS deps
+WORKDIR /app
+COPY package.json package-lock.json* ./
+RUN npm ci
+
+FROM node:20-alpine AS builder
+WORKDIR /app
+ARG NEXT_PUBLIC_API_URL=http://localhost:9080/api/v1
+ENV NEXT_PUBLIC_API_URL=$NEXT_PUBLIC_API_URL
+COPY --from=deps /app/node_modules ./node_modules
+COPY . .
+RUN npm run build
+
+FROM node:20-alpine AS runner
+WORKDIR /app
+ENV NODE_ENV=production
+COPY --from=builder /app/.next/standalone ./
+COPY --from=builder /app/.next/static ./.next/static
+COPY --from=builder /app/public ./public
+EXPOSE 3000
+CMD ["node", "server.js"]