Plugins running in iframe sandboxes previously lacked access to the user's regional formatting settings (dateLocale, timeFormat 12h/24h, timeZone, and firstDayOfWeek) unless they requested privileged settings:read permissions.
This mirrors the host's resolved presentation preferences into the plugin sandbox:
- Adds RegionalSnapshot (locale, dateLocale, hour12, timeZone, firstDayOfWeek) to BackgroundInit, SlotInit, and LocaleChangeMsg.
- Implements snapshotRegionalSettings() in host-bridge, reusing host resolveDateLocale() and getEffectiveTimeZone().
- Subscribes stores/plugin-store.ts to useSettingsStore to broadcast updates to running sandboxes when regional preferences change.
- Exposes api.i18n.formatTime(date, options) and api.i18n.formatDate(date, options) along with regional getters on api.i18n.
- Add Combobox component supporting single and multiselect modes, search filtering, and clear button
- Implement floating dropdown bridge and host slot portal so dropdown renders cleanly outside plugin iframe
- Fix clear button and chip removals to not unexpectedly open the dropdown
- Add comprehensive unit tests covering Combobox options, clear behavior, multiselect, and bridge communication