feat: Ford legacy support, EMEX browser pooling, collapsible sidebar

- Add PL24 Ford legacy service for fordt_parts architecture
- Refactor EMEX to use persistent browser pool instead of per-call instances
- Make vehicle decode resilient: fallback to PL24 when Corgi doesn't recognize VIN
- Add collapsible sidebar with persistent user preference
- Improve brand access guard and categories service
- Add debug/test scripts for VIN e2e testing

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/api/src/parts/parts.service.ts

@@ -63,7 +63,10 @@ export class PartsService {
         description: p.description || null,
         quantity: p.quantity || null,
         position: p.positionCode || null,
-        hotspotIndex: p.hotspotId ? parseInt(p.hotspotId, 10) || null : null,
+        hotspotIndex: p.hotspotId ? (() => {
+          const val = parseInt(p.hotspotId!, 10);
+          return (val > 0 && val <= 2147483647) ? val : null;
+        })() : null,
         source: "pl24" as const,
       }));