Fix OpenAPI endpoint to serve swagger.json directly

internal/server/routes.go

@@ -2,7 +2,6 @@ package server
 
 import (
 	"fmt"
-	"music-server/cmd/docs"
 	"music-server/cmd/web"
 	"net/http"
 	"sort"
@@ -31,11 +30,10 @@ func (s *Server) RegisterRoutes() http.Handler {
 	e := echo.New()
 	
 	// Serve OpenAPI spec at /openapi
-	e.GET("/openapi", func(c echo.Context) error {
-		c.Response().Header().Set("Content-Type", "application/json")
-		_, err := c.Response().Write([]byte(docs.GetSwaggerJSON()))
-		return err
-	})
+	e.GET("/openapi", echo.WrapHandler(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		http.ServeFile(w, r, "cmd/docs/swagger.json")
+	})))
 	e.Use(middleware.Logger())
 	e.Use(middleware.Recover())