Implemented version display in SiteHeader of webui

- Updated API version to 1.2.0
- Stored versions in localStorage

lightrag_webui/src/api/lightrag.ts

@@ -132,6 +132,8 @@ export type AuthStatusResponse = {
   token_type?: string
   auth_mode?: 'enabled' | 'disabled'
   message?: string
+  core_version?: string
+  api_version?: string
 }
 
 export type LoginResponse = {
@@ -139,6 +141,8 @@ export type LoginResponse = {
   token_type: string
   auth_mode?: 'enabled' | 'disabled'  // Authentication mode identifier
   message?: string                    // Optional message
+  core_version?: string
+  api_version?: string
 }
 
 export const InvalidApiKeyError = 'Invalid API Key'