Add createJWTMiddleware helper that sets database.Users object in context,
matching the original main.go JWT middleware behavior. This fixes
'authentication context error' panics in handlers that call
MustGetAuthenticatedUser.
Changes:
- Add createJWTMiddleware() in router.go
- Update all route files to use the helper
- Set user claims AND database.Users object in context
Add stub implementations for:
- library.go: Library management routes (admin + user visibility)
- device.go: Device registration and management routes
- router.go: Updated to import jwt package
Router package structure is complete with all route groups defined.
Next step: Incrementally migrate routes from main.go by calling
router.RegisterRoutes() and removing duplicate definitions.
All verification checks pass (26/26).