Add Thai language support for various application components

- Introduced Thai translations for dashboard, knowledge, login, models, scripts, settings, skills, task, and common UI elements.
- Updated provider placeholders to include Thai language options.
- Modified locale resolution to support Thai language.
- Adjusted settings store to handle legacy language migration from Japanese to Thai.
- Enhanced runtime types to include Thai as a supported language.

src/i18n/constants.ts

@@ -1,13 +1,13 @@
 import type { LanguageCode } from '../types/runtime';
 
-export const SUPPORTED_LANGUAGE_CODES = ['en', 'zh', 'ja'] as const satisfies readonly LanguageCode[];
+export const SUPPORTED_LANGUAGE_CODES = ['en', 'zh', 'th'] as const satisfies readonly LanguageCode[];
 
 export type { LanguageCode };
 
 export const SUPPORTED_LANGUAGES = [
   { code: 'en', label: 'English' },
   { code: 'zh', label: '中文' },
-  { code: 'ja', label: '日本語' },
+  { code: 'th', label: 'ไทย' },
 ] as const;
 
 export type Namespace =