server: send 405 instead of 404 for unallowed methods (#10275)

Fixes: #5483

server/routes.go

@@ -1170,6 +1170,7 @@ func (s *Server) GenerateRoutes(rc *ollama.Registry) (http.Handler, error) {
 	corsConfig.AllowOrigins = envconfig.AllowedOrigins()
 
 	r := gin.Default()
+	r.HandleMethodNotAllowed = true
 	r.Use(
 		cors.New(corsConfig),
 		allowedHostsMiddleware(s.addr),