fix(dates): block past-date selection in appointment + clinic holiday pickers

Bug 556 triggered a broader audit of every date input in the app:

 - appointment-form DatePicker now has minValue=today(getLocalTimeZone()) —
   can't book or reschedule into the past (tightens bug 555 at the
   input layer too; the past-slot filter in masterdata service still
   handles the hour-granularity)
 - clinic-form holiday date picker gets the same — can't observe a
   holiday that already passed

Audit complete:
 - enquiry-form follow-up date: already had min=today (bug 556 fix)
 - appointment-form: fixed here
 - clinic-form holidays: fixed here
 - my-performance date filter: past valid (reports over history)
 - campaign-edit start/end: past valid (historical campaigns)

src/components/call-desk/appointment-form.tsx

@@ -6,7 +6,7 @@ import { Select } from '@/components/base/select/select';
 import { TextArea } from '@/components/base/textarea/textarea';
 import { Button } from '@/components/base/buttons/button';
 import { DatePicker } from '@/components/application/date-picker/date-picker';
-import { parseDate } from '@internationalized/date';
+import { parseDate, today, getLocalTimeZone } from '@internationalized/date';
 import { apiClient } from '@/lib/api-client';
 import { cx } from '@/utils/cx';
 import { notify } from '@/lib/toast';
@@ -586,6 +586,11 @@ export const AppointmentForm = ({
                         onChange={(val) => setDate(val ? val.toString() : '')}
                         granularity="day"
                         isDisabled={readOnly || !doctor}
+                        // Block past dates — appointments can't be booked or
+                        // rescheduled into the past. React Aria's DatePicker
+                        // honours minValue in both the calendar grid and the
+                        // typed-input fallback.
+                        minValue={today(getLocalTimeZone())}
                     />
                 </div>
 

src/components/forms/clinic-form.tsx

@@ -399,6 +399,9 @@ export const ClinicForm = ({ value, onChange }: ClinicFormProps) => {
                                 onChange={(dv: DateValue | null) =>
                                     updateHoliday(idx, { date: dv ? dv.toString() : '' })
                                 }
+                                // Holidays must be today or in the future — you
+                                // can't observe a holiday that already passed.
+                                minValue={today(getLocalTimeZone())}
                             />
                         </div>
                         <div className="flex-1">