/**
 * Resolves the locale used by `DateField` for placeholder, parsing, and display formatting.
 *
 * Date format is a *regional* preference (e.g. `dd/mm/yyyy` vs `mm/dd/yyyy`), independent of the
 * UI translation language. We therefore prefer `navigator.language` — a region-qualified browser
 * locale (`en-GB`, `en-US`, `fr-CA`, `da-DK`, …) is the user's explicit regional preference and
 * wins over the user-selected Manager UI language. The selected language is only used as a
 * fallback when the browser locale is missing or has no region.
 *
 * Examples (selected | browser → resolved):
 * - `en` | `en-GB` → `en-GB` (UK customers see `dd/mm/yyyy`)
 * - `en` | `en-US` → `en-US` (US customers see `mm/dd/yyyy`)
 * - `da` | `en-US` → `en-US` (browser region wins for date format)
 * - `da` | `da-DK` → `da-DK` (`dd.mm.yyyy`, dotted separator is the native Danish format)
 * - `en` | `en` (no region) → falls through to `resolveDateFieldLocale`, which keeps `en`
 * - `cimode` | `en-US` → `en-US` (browser wins; i18next's key-debug pseudo-language is non-Intl)
 * - `cimode` | `en` → `en` (`resolveDateFieldLocale` filters `cimode` out and returns the browser locale)
 *
 * Note: this hook reads `localStorage` and `navigator.language` synchronously and does not
 * subscribe to changes. Re-renders on same-tab language change rely on the consuming component
 * also using `useTranslation` (which re-renders on `i18next.languageChanged`). Cross-tab sync
 * is not supported.
 */
export declare const useDateFieldLocale: () => string;