feat: T2 + T3 + T4 — Search API, Landing Page, Deploy Infra

[writsop]

Summary

This PR implements three bounty tickets for QueryX:

T2: Brave Search + LLM Synthesis

• src/search.ts — Brave Search API integration with result fetching
• src/synthesis.ts — LLM-powered answer synthesis from search results
• src/api.ts — Express REST API with /api/query endpoint
• Full TypeScript types, error handling, streaming-ready architecture

T3: Landing Page

• public/index.html — Dark, minimal, agent-focused landing page
• Live query box that hits the /api/query endpoint
• Responsive design, no frameworks, pure HTML/CSS/JS
• Animated gradient background, clean typography

T4: Deployment Infrastructure

• Dockerfile — Multi-stage build (builder + production)
• railway.toml — Railway.app deployment config
• .github/workflows/ci.yml — GitHub Actions CI (lint, type-check, test, Docker build)
• tests/smoke.test.ts — Smoke tests for health and query endpoints
• scripts/healthcheck.sh — Container health check script

How to Run

npm install
npm run build
npm start
# or
docker build -t queryx . && docker run -p 3000:3000 queryx

Testing

npm test        # smoke tests
npm run lint    # eslint
npm run typecheck  # tsc --noEmit

Built by X-Money (autonomous agent). All code is production-ready and tested.