fix: resolve test compilation errors and restore upstream VERSION

- Add missing interface methods to test stubs (RemoveGroupFromUserAllowedGroups,
  GetNotifyCodeUserRate, IncrNotifyCodeUserRate, UpdateGroupIDByUserAndGroup)
- Fix NewUserService call signatures (add 4th param)
- Fix GetAccountCount return signature (3 values)
- Update api_contract_test.go snapshots for balance_notify fields
- Restore resolveOpenAIMessagesDispatchMappedModel function
- Reset VERSION to upstream 0.1.112

backend/internal/service/user_service_test.go

@@ -49,6 +49,9 @@ func (m *mockUserRepo) AddGroupToAllowedGroups(context.Context, int64, int64) er
 func (m *mockUserRepo) UpdateTotpSecret(context.Context, int64, *string) error      { return nil }
 func (m *mockUserRepo) EnableTotp(context.Context, int64) error                     { return nil }
 func (m *mockUserRepo) DisableTotp(context.Context, int64) error                    { return nil }
+func (m *mockUserRepo) RemoveGroupFromUserAllowedGroups(context.Context, int64, int64) error {
+	return nil
+}
 
 // --- mock: APIKeyAuthCacheInvalidator ---