feat: add registration invite code handling and improve error translations

- Updated AuthViews component to conditionally show invite code field based on registrationInviteRequired prop.
- Enhanced error handling in auth API functions to use translateServerError for better user feedback.
- Added new translations for various server error messages in English, Spanish, Russian, Chinese (Simplified and Traditional).
- Modified demo initial bootstrap state to include registrationInviteRequired flag.
- Updated types to include registrationInviteRequired in WebBootstrapResponse.

webapp/src/lib/demo.empty.ts

@@ -19,6 +19,7 @@ export function createDemoBackupSettings(): AdminBackupSettings {
 export function createDemoInitialBootstrapState(): InitialAppBootstrapState {
   return {
     defaultKdfIterations: 600000,
+    registrationInviteRequired: true,
     jwtWarning: null,
     session: null,
     phase: 'login',