feat: 新增工作室展示开关 VITE_STUDIO_ENABLED

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend-web/src/env.ts

@@ -8,7 +8,8 @@ function readEnv(
     | "VITE_NOTE_API_BASE_URL"
     | "VITE_NOTEBOOK_API_BASE_URL"
     | "VITE_STATIC_WEBSITE_ONLY"
-    | "VITE_GITHUB_OAUTH_TOKEN",
+    | "VITE_GITHUB_OAUTH_TOKEN"
+    | "VITE_STUDIO_ENABLED",
 ): EnvValue {
   const value = import.meta.env[key];
   return typeof value === "string" && value.trim() ? value : undefined;
@@ -24,4 +25,5 @@ export const env = {
   NEXT_PUBLIC_NOTEBOOK_API_BASE_URL: readEnv("VITE_NOTEBOOK_API_BASE_URL"),
   NEXT_PUBLIC_STATIC_WEBSITE_ONLY: readEnv("VITE_STATIC_WEBSITE_ONLY"),
   GITHUB_OAUTH_TOKEN: readEnv("VITE_GITHUB_OAUTH_TOKEN"),
+  STUDIO_ENABLED: readEnv("VITE_STUDIO_ENABLED"),
 };