Add common translation keys and localize account holder search request page

- Add common translation keys: select, requestSuccess, requestFailed, errorOccurred
- Replace hardcoded '선택' with t('common.select') in account holder search request page
- Fix KeyIn enum: uncomment FULL_CANCEL and PARTIAL_CANCEL to resolve TypeScript errors
- All labels now support Korean and English through i18n

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/pages/additional-service/account-holder-search/request-page.tsx

@@ -117,7 +117,7 @@ export const AccountHolderSearchRequestPage = () => {
                                     <div className="billing-label">{t('transaction.fields.bank')}</div>
                                     <div className="billing-field">
                                         <select value={formData.bankCode} onChange={(e) => handleInputChange('bankCode', e.target.value)}>
-                                            <option value="">{t('common.pleaseSelect')}</option>
+                                            <option value="">{t('common.select')}</option>
                                             {
                                                 bankList
                                                     .filter((bank) => bank.code1 !== '****')