Add bun integration tests for docs flow, update integration guide

- Add test/integration.test.ts: getServicePublicKey, full flow (register, login, createCollection, createPointFeature, listFeatures)
- Update docs example: registerBySigningServiceKey then loginWithSignature
- Document integration tests in typescript-frontend-integration.md

Made-with: Cursor

AGENTS.md

@@ -7,7 +7,7 @@ This file gives future coding agents a fast path map for this repository.
 - API entrypoint: `cmd/api/main.go`
 - HTTP routes/handlers: `internal/http/handlers.go`
 - Core domain logic: `internal/app/service.go`
-- In-memory persistence: `internal/store/`
+- Persistence: `internal/store/` — PostgreSQL (when `DATABASE_URL` set) or in-memory; migrations in `internal/store/migrations/`
 - Auth utilities: `internal/auth/`
 - Frontend static app: `web/`
 - TypeScript API client: `libs/geo-api-client/`