feat(T1): Core Lucid Agent — x402 paid API with TDD

[openpango]

Summary

Implements the core Queryx Lucid Agent with x402 USDC micropayments on Base Mainnet.

What's included

• Zod v4 schemas for all endpoints (request, response, error, health)
• Search orchestration layer: brave search → rank/dedup → LLM synthesis → in-memory cache
• 3 paid endpoints: GET /v1/search, GET /v1/search/news, POST /v1/search/deep
• Health endpoint: GET /health (free, no payment required)
• Lucid Agent setup with @lucid-agents/core, @lucid-agents/hono, @lucid-agents/payments
• x402 pricing: $0.001 USDC per search/news, $0.005 USDC per deep research
• 60 tests passing across contract, logic, integration, and freshness suites

Acceptance criteria

• All monetized endpoints return HTTP 402 without valid x402 payment
• All monetized endpoints return valid JSON after payment
• All responses include freshness and confidence fields
• 60 tests passing (bun test clean)
• Server uses export default { port, fetch: app.fetch }
• Zod v4 schemas throughout

Closes #1