feat: implement comprehensive configuration validation and integrate into store loading and server initialization.

app/handler.go

@@ -3,9 +3,17 @@ package app
 import (
 	"net/http"
 
+	"ds2api/internal/config"
 	"ds2api/internal/server"
 )
 
 func NewHandler() http.Handler {
-	return server.NewApp().Router
+	app, err := server.NewApp()
+	if err != nil {
+		config.Logger.Error("[app] init failed", "error", err)
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			server.WriteUnhandledError(w, err)
+		})
+	}
+	return app.Router
 }