開発モードで警告を表示するようにするなど

src/client/app/config.ts

@@ -4,6 +4,7 @@ declare const _THEME_COLOR_: string;
 declare const _COPYRIGHT_: string;
 declare const _VERSION_: string;
 declare const _CODENAME_: string;
+declare const _ENV_: string;
 
 const address = new URL(location.href);
 
@@ -18,3 +19,4 @@ export const themeColor = _THEME_COLOR_;
 export const copyright = _COPYRIGHT_;
 export const version = _VERSION_;
 export const codename = _CODENAME_;
+export const env = _ENV_;