frontend phase 0: app shells, design system & data/contract patterns

Turn the starter into the Balinyaar foundation for the three actor
experiences and lock in the patterns later phases copy.

- Cleanup: remove toastDemo namespace, placeholder home page, and the two
  dead icons; fix BottomBar to use usePathname (locale-aware active tab).
- Three actor shells under (private-routes), no layout above [locale]:
  customer (customer) group with the 5-tab bottom nav; nurse (/nurse) and
  admin (/admin) on the shared sidebar engine. Role model via constants/roles
  + useActorRole (defaults to customer until roles land in f1-b2).
- services/{domain} reference (patients) with a mock behind a config seam,
  hierarchical query keys, deliberate staleTime, and mutation invalidation;
  shared ApiEnvelope/Paginated wire types + unwrap() in lib/api/types.
- Money (integer-safe IRR/Toman) + Shamsi-date utils; toEnglishDigits helper.
- Shared composites, each tested: OtpInput, PhoneNumberField, StepperHeader,
  StatusChip, PlaceholderScreen.
- i18n: seed nav/common/shell/patients in both locales; document namespace
  conventions. Update client/CLAUDE.md Project Structure + fix ColorSchemeScript
  doc drift. Add phase report, STATUS, and REQ-001 (envelope/casing/pagination).

Gate: npm run check + test:ci green (72 tests); build green with NEXT_PUBLIC_API_URL.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

client/src/utils/date.ts

@@ -0,0 +1,34 @@
+/**
+ * Date display helpers. Timestamps cross the wire as UTC ISO-8601; Shamsi (Persian
+ * calendar) display is a client concern (see money-and-types.md). We render via the
+ * Intl Persian calendar — no date library needed.
+ */
+
+const SHAMSI_LOCALE = 'fa-IR-u-ca-persian';
+
+/** Resolves the Intl locale for date formatting from the app locale. */
+function intlLocale(locale: string): string {
+  return locale === 'fa' ? SHAMSI_LOCALE : 'en-US';
+}
+
+/** Formats a UTC ISO timestamp as a localized date (Shamsi for `fa`, Gregorian for `en`). */
+export function formatShamsiDate(
+  iso: string | Date,
+  locale: string = 'fa',
+  options: Intl.DateTimeFormatOptions = { year: 'numeric', month: 'long', day: 'numeric' }
+): string {
+  const date = iso instanceof Date ? iso : new Date(iso);
+  if (Number.isNaN(date.getTime())) return '';
+  return new Intl.DateTimeFormat(intlLocale(locale), options).format(date);
+}
+
+/** Formats a UTC ISO timestamp as a localized date + time. */
+export function formatShamsiDateTime(iso: string | Date, locale: string = 'fa'): string {
+  return formatShamsiDate(iso, locale, {
+    year: 'numeric',
+    month: 'long',
+    day: 'numeric',
+    hour: '2-digit',
+    minute: '2-digit',
+  });
+}