feat(agenda): Epic 4 - EPD Koppeling (appointment-report integration)

Implements bidirectional linking between appointments and reports:
- E4.S1: Create report from appointment modal with encounter pre-linked
- E4.S2: Link existing reports to appointments via EncounterSelector
- E4.S3: Show linked reports in appointment modal edit view
- E4.S4: Navigation between appointments and reports with deep linking

Also includes bug fixes for patient search:
- Fix FHIR to internal format mapping for patient data
- Fix debounced search interference after patient selection
- Fix UUID handling for optional practitioner_id

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

app/epd/agenda/page.tsx

@@ -5,15 +5,29 @@
  * Supports day, week, and workweek views.
  */
 
-import { startOfWeek, endOfWeek } from 'date-fns';
+import { startOfWeek, endOfWeek, parseISO, isValid } from 'date-fns';
 import { AgendaView } from './components/agenda-view';
 import { getEncounters } from './actions';
 
-export default async function AgendaPage() {
-  // Get initial date range (current week)
-  const now = new Date();
-  const start = startOfWeek(now, { weekStartsOn: 1 });
-  const end = endOfWeek(now, { weekStartsOn: 1 });
+interface AgendaPageProps {
+  searchParams: Promise<{ date?: string; encounterId?: string }>;
+}
+
+export default async function AgendaPage({ searchParams }: AgendaPageProps) {
+  const { date: dateParam, encounterId } = await searchParams;
+
+  // Parse date from URL or use current date
+  let targetDate = new Date();
+  if (dateParam) {
+    const parsedDate = parseISO(dateParam);
+    if (isValid(parsedDate)) {
+      targetDate = parsedDate;
+    }
+  }
+
+  // Get initial date range (week of target date)
+  const start = startOfWeek(targetDate, { weekStartsOn: 1 });
+  const end = endOfWeek(targetDate, { weekStartsOn: 1 });
 
   // Fetch initial events
   const initialEvents = await getEncounters({
@@ -24,7 +38,8 @@ export default async function AgendaPage() {
   return (
     <AgendaView
       initialEvents={initialEvents}
-      initialDate={now}
+      initialDate={targetDate}
+      highlightEncounterId={encounterId}
     />
   );
 }