fix(cortex): integrate intake intents into full chat + artifact flow

Fixes 4 bugs preventing intake blocks from working:

1. Chat API validation: Add 'nudge' to message type enum, allow empty
   content for streaming messages
2. AI chat recognition: Add P3 intake intents (intake_status,
   risico_query, diagnose_query, intake_navigeer) to system prompt
   with triggers, entities, and JSON examples
3. Artifact rendering: Add intake block imports and switch cases
   to artifact-container.tsx
4. API 400 error: Convert null to undefined for optional Zod params
   (searchParams.get returns null, Zod .optional() expects undefined)

Also adds:
- Testplan for E2E testing (60+ test cases)
- Session log with lessons learned and new intent checklist

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

components/cortex/artifacts/artifact-container.tsx

@@ -18,6 +18,10 @@ import { ZoekenBlock } from '../blocks/zoeken-block';
 import { OverdrachtBlock } from '../blocks/overdracht-block';
 import { PatientDashboardBlock } from '../blocks/patient-dashboard-block';
 import { FallbackPicker } from '../blocks/fallback-picker';
+// Intake MVP blocks
+import { IntakeStatusBlock } from '../blocks/intake-status-block';
+import { RisicoBlock } from '../blocks/risico-block';
+import { DiagnoseBlock } from '../blocks/diagnose-block';
 import { APPOINTMENT_TYPES, type AppointmentTypeCode, type LocationClassCode } from '@/app/epd/agenda/types';
 import type { Artifact, BlockType } from '@/stores/cortex-store';
 import { parseRelativeDate, isDateRange } from '@/lib/cortex/date-time-parser';
@@ -194,6 +198,13 @@ function renderArtifactBlock(artifact: Artifact, onCloseArtifact: (id: string) =
       return <PatientDashboardBlock key={artifact.id} prefill={artifact.prefill} />;
     case 'fallback':
       return <FallbackPicker key={artifact.id} originalInput={artifact.prefill?.content} />;
+    // Intake MVP blocks
+    case 'intake_status':
+      return <IntakeStatusBlock key={artifact.id} prefill={artifact.prefill} />;
+    case 'risico_query':
+      return <RisicoBlock key={artifact.id} prefill={artifact.prefill} />;
+    case 'diagnose_query':
+      return <DiagnoseBlock key={artifact.id} prefill={artifact.prefill} />;
     default:
       return (
         <div className="p-4 text-slate-500">
@@ -232,6 +243,13 @@ export function getArtifactTitle(type: BlockType, prefill?: any): string {
       return prefill?.patientName
         ? `Dashboard - ${prefill.patientName}`
         : 'Patiëntoverzicht';
+    // Intake MVP blocks
+    case 'intake_status':
+      return 'Intake Status';
+    case 'risico_query':
+      return 'Risicotaxatie';
+    case 'diagnose_query':
+      return 'Diagnoses';
     default:
       return 'Artifact';
   }