refactor(cortex): Epic 0 - Extract patient search hooks & components (E0.S1-S4)

DRY refactor: Extract reusable patient search logic from ZoekenBlock.

New files:
- lib/cortex/hooks/use-patient-search.ts (116 lines)
  Debounced patient search with abort controller
- lib/cortex/hooks/use-patient-selection.ts (98 lines)
  FHIR fetch + store update flow
- lib/fhir/patient-mapper.ts (109 lines)
  FHIR Patient to DB Patient mapping + utilities
- components/cortex/shared/patient-list-item.tsx (114 lines)
  Reusable patient list item with loading states

Refactored:
- ZoekenBlock: 349 -> 127 lines (-64%)

Documentation:
- docs/intent/patient-search/ux-analyse-patient-selectie.md
- docs/intent/patient-search/bouwplan-patient-selectie-v1.md

CLAUDE.md updated with Cortex architecture documentation.

Epic 0 complete: 4/4 stories (4 SP)

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

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

lib/cortex/hooks/index.ts

@@ -0,0 +1,8 @@
+/**
+ * Cortex Hooks
+ *
+ * Reusable hooks for Cortex functionality.
+ */
+
+export { usePatientSearch, type PatientSearchResult } from './use-patient-search';
+export { usePatientSelection } from './use-patient-selection';