🔐 feat: add JWT authentication support to Swagger UI

- Added ApiKeyAuth security definition for JWT Bearer token authentication
- Configured security scheme with Authorization header and Bearer token format
- Added @Security annotations to greet endpoints (v1 GET, v2 POST) for optional authentication
- Updated Swagger documentation to show authentication requirements
- Maintained backward compatibility - authentication remains optional for greet endpoints

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

cmd/server/main.go

@@ -15,6 +15,11 @@
 //	@host		localhost:8080
 //	@BasePath	/api
 //	@schemes	http https
+//
+//	@securityDefinitions.apikey	ApiKeyAuth
+//	@in				header
+//	@name			Authorization
+//	@description	JWT authentication using Bearer token. Format: Bearer <token>
 
 package main