fix(web): resolve all 22 TypeScript typecheck errors in apps/web (TEC-3208)

- Fix TS4111: use bracket notation for index signature access in metadata.spec.ts,
  neighborhood-poi-map.tsx, and neighborhood-poi-map.spec.tsx
- Fix TS2740: add missing property fields (usableAreaM2, floor, totalFloors,
  nearbyPOIs, etc.) to test mock objects in 5 spec files
- Fix TS2339: add missing estimate() and create() methods to transferApi
- Fix TS4114: add override modifier to render() in page.tsx error boundary
- Fix TS2532: add optional chaining for possibly undefined features in
  neighborhood-poi-map.tsx

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/web/components/neighborhood/__tests__/neighborhood-poi-map.spec.tsx

@@ -228,7 +228,7 @@ describe('NeighborhoodPOIMap', () => {
 
     expect(capturedData).not.toBeNull();
     expect(capturedData!.features).toHaveLength(2);
-    expect(capturedData!.features.map((f) => f.properties?.category)).not.toContain('school');
+    expect(capturedData!.features.map((f) => f.properties?.['category'])).not.toContain('school');
   });
 
   // ── Loading state ─────────────────────────────────────────────────────────────