cmd/pkgserver: move ui internal

This avoids inadvertently exporting a go package. This change also cleans up generate layout.

Signed-off-by: Ophestra <cat@gensokyo.uk>

cmd/pkgserver/main.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"hakurei.app/check"
+	"hakurei.app/cmd/pkgserver/internal/ui"
 	"hakurei.app/command"
 	"hakurei.app/internal/pkg"
 	"hakurei.app/internal/rosa"
@@ -81,7 +82,7 @@ func main() {
 			}
 		}()
 		var mux http.ServeMux
-		uiRoutes(&mux)
+		ui.Register(&mux)
 		index.registerAPI(&mux)
 		server := http.Server{
 			Addr:    flagAddr,