Add REST-idiomatic DELETE method as alias for POST .../delete.
Add 8 router-level tests exercising Bearer auth, invalid tokens,
soft delete, export body decoding, and MaxLauncherHR capping.
Create OpenAPI 3.1.0 specification covering all v2 endpoints.
Introduces incremental API improvements for custom launcher support
(mhf-iel, stratic-dev's Rust launcher):
- Standardize all error responses to JSON envelopes with error/message
- Add Bearer token auth middleware for v2 routes (legacy body-token preserved)
- Add `returning` (>90d inactive) and `courses` fields to auth response
- Add /v2/ route prefix with HTTP method enforcement
- Add GET /v2/server/status for MezFes, featured weapon, and event status
- Add APIEventRepo for read-only event data access
Closes#44
