🔐 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>

pkg/greet/api_v2.go

@@ -55,6 +55,7 @@ type greetResponse struct {
 //	@Param			request	body		GreetRequest	true	"Greeting request"
 //	@Success		200		{object}	GreetResponseV2	"Successful response"
 //	@Failure		400		{object}	ValidationError	"Validation error"
+//	@Security		ApiKeyAuth
 //	@Router			/v2/greet [post]
 func (h *apiV2GreetHandler) handleGreetPost(w http.ResponseWriter, r *http.Request) {
 	// Read request body