feat: initialize ingest-api with Koa and telemetry handling

- Create ingest-api with Koa framework for handling device telemetry.
- Implement telemetry ingestion with MongoDB, Redis, and PostgreSQL.
- Add API endpoints for telemetry and health checks.
- Set up testing with Vitest for unit and end-to-end tests.
- Configure Prettier and ESLint for code formatting and linting.
- Create Docker Compose setup for PostgreSQL, MongoDB, and Redis services.
- Establish contracts package for shared Zod schemas and TypeScript types.
- Implement React frontend with device status and greeting functionalities.
- Add VS Code setup documentation for onboarding developers.

infra/postgres/init.sql

@@ -0,0 +1,6 @@
+CREATE TABLE IF NOT EXISTS device_current_state (
+  device_id TEXT PRIMARY KEY,
+  payload JSONB NOT NULL DEFAULT '{}'::jsonb,
+  last_seen TIMESTAMPTZ NOT NULL,
+  updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);