Refactor router setup to split routes by auth/protected boundary

internal/server/routes_protected.go

@@ -0,0 +1,12 @@
+package server
+
+import (
+	"github.com/gin-gonic/gin"
+
+	"github.com/dhao2001/mygo/internal/app"
+)
+
+func setupProtectedRoutes(rg *gin.RouterGroup, _ *app.WebApp) {
+	_ = rg
+	// Protected routes will be registered after auth middleware is implemented.
+}