feat(12.2-04): add the datepicker field and stored date and time list cells

- pin @internationalized/date 3.12.4 as a direct admin dependency (approved)
- dateFormat.ts parses and emits date, datetime (local display, UTC emit,
  ignoreTimezone wall clock) and time values without the global Date
- DatepickerField on Reka DatePicker and TimeField with locale segments,
  calendar popover, clear button, min/max and yearRange bounds
- list cells of type date and time render the stored string
- datepicker lang keys in en and pl; rebuilt boardwalk dist

admin/tests/fixtures/deferred.form-schema.json

@@ -8,6 +8,20 @@
         "type": "text",
         "required": true
       },
+      {
+        "name": "starts_at",
+        "label": "Starts at",
+        "type": "datepicker",
+        "mode": "datetime"
+      },
+      {
+        "name": "released_on",
+        "label": "Released on",
+        "type": "datepicker",
+        "mode": "date",
+        "minDate": "2026-01-01",
+        "displayFormat": "D MMMM YYYY"
+      },
       {
         "name": "photos",
         "label": "Photos",