feat(api): add site events REST endpoints and dashboard integration

[heydemoura]

Summary

• Add a new REST API surface for site events and integrate it into the dashboard/server wiring.
• Harden migration behavior to reconcile state instead of failing hard in partially migrated environments.
• Improve onboarding and operator documentation with a new getting-started guide and cross-links.

Key Changes vs Base (v2-add-site-events)

• New API layer
  • Added internal/dashboard/api.go with authenticated REST handlers under /api/v1.
  • Updated internal/dashboard/dashboard.go and cmd/jetmon2/main.go to serve dashboard + API on the same listener.
  • Added API behavior for site management and event reads, including auth/rate-limit handling.
• DB + query path updates
  • Updated internal/db/queries.go and internal/db/site_events.go for site CRUD/event-read support used by the API.
  • Added/updated tests in internal/db/queries_test.go and internal/dashboard/dashboard_test.go.
• Migration resilience
  • Updated internal/db/migrations.go to reconcile migration 8 schema pieces idempotently (instead of hard-failing when columns/index already exist), so later migrations can still apply.
• Config and local infra
  • Updated internal/config/config.go and internal/config/config_test.go with API token/rate-limit config behavior.
  • Updated docker/docker-compose.yml for container naming adjustment.
• Docs
  • Added GETTING_STARTED.md.
  • Added references in README.md, PROJECT.md, and config/config.readme.

Testing

• go test ./internal/dashboard ./internal/db ./internal/config ./cmd/jetmon2
• go test ./internal/db

Risk / Rollout

• Primary risk is migration/query behavior touching site-event paths.
• Mitigations:
  • Validate migrations on fresh and pre-existing DB states.
  • Verify API auth and endpoint behavior in Docker.
  • Roll out with normal rolling update and monitor migration/API logs.