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/web/src/lib/user-settings.ts

@@ -2,10 +2,12 @@ const STORAGE_KEY = "userSettings";
 
 interface UserSettings {
   categoryViewMode?: "grid" | "tree";
+  sidebarCollapsed?: boolean;
 }
 
 const defaults: UserSettings = {
   categoryViewMode: "grid",
+  sidebarCollapsed: false,
 };
 
 export function getUserSettings(): UserSettings {