feat(i18n): 添加 AI Studio OAuth 配置状态相关文案

- 添加 aiStudioNotConfiguredShort/Tip/aiStudioNotConfigured 翻译
- 更新 needsProjectIdDesc/noProjectIdNeededDesc 描述更准确

frontend/src/i18n/locales/en.ts

@@ -961,9 +961,14 @@ export default {
 	          stateWarningDesc: 'Recommended: paste the full callback URL (includes code & state).',
 	          oauthTypeLabel: 'OAuth Type',
 	          needsProjectId: 'For GCP Developers',
-	          needsProjectIdDesc: 'Uses built-in client, requires GCP project',
+	          needsProjectIdDesc: 'Requires GCP project',
 	          noProjectIdNeeded: 'For Regular Users',
-	          noProjectIdNeededDesc: 'Requires your own OAuth client'
+	          noProjectIdNeededDesc: 'Requires admin-configured OAuth client',
+	          aiStudioNotConfiguredShort: 'Not configured',
+	          aiStudioNotConfiguredTip:
+	            'AI Studio OAuth is not configured: set GEMINI_OAUTH_CLIENT_ID / GEMINI_OAUTH_CLIENT_SECRET and add Redirect URI: http://localhost:1455/auth/callback (Consent screen scopes must include https://www.googleapis.com/auth/generative-language.retriever)',
+	          aiStudioNotConfigured:
+	            'AI Studio OAuth is not configured: set GEMINI_OAUTH_CLIENT_ID / GEMINI_OAUTH_CLIENT_SECRET and add Redirect URI: http://localhost:1455/auth/callback'
 	        }
 	      },
       // Gemini specific (platform-wide)

frontend/src/i18n/locales/zh.ts

@@ -1069,9 +1069,12 @@ export default {
 	          stateWarningDesc: '建议粘贴完整回调链接（包含 code 和 state）。',
 	          oauthTypeLabel: 'OAuth 类型',
 	          needsProjectId: '适合 GCP 开发者',
-	          needsProjectIdDesc: '使用内置客户端，需 GCP 项目',
+	          needsProjectIdDesc: '需 GCP 项目',
 	          noProjectIdNeeded: '适合普通用户',
-	          noProjectIdNeededDesc: '需自建 OAuth Client'
+	          noProjectIdNeededDesc: '需管理员配置 OAuth Client',
+	          aiStudioNotConfiguredShort: '未配置',
+	          aiStudioNotConfiguredTip: 'AI Studio OAuth 未配置：请先设置 GEMINI_OAUTH_CLIENT_ID / GEMINI_OAUTH_CLIENT_SECRET，并在 Google OAuth Client 添加 Redirect URI：http://localhost:1455/auth/callback（Consent Screen scopes 需包含 https://www.googleapis.com/auth/generative-language.retriever）',
+	          aiStudioNotConfigured: 'AI Studio OAuth 未配置：请先设置 GEMINI_OAUTH_CLIENT_ID / GEMINI_OAUTH_CLIENT_SECRET，并在 Google OAuth Client 添加 Redirect URI：http://localhost:1455/auth/callback'
 	        }
 	      },
       // Gemini specific (platform-wide)