feat(manufacturers): detail page with MPN-level insights

Adds /manufacturers/:id with vendor-wide KPIs, top MPNs by units,
failures by MPN, category mix, past-EOL exposure, and a filtered
PartModels table. Wires upstream links from PartDetail and
PartModelDetail so the manufacturer name is a navigable anchor.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

apps/api/src/routes/manufacturers.ts

@@ -11,6 +11,8 @@ import { validate } from '../middleware/validate.js';
 const router = Router();
 
 router.get('/', requireAuth, validate('query', PaginationQuery), ctrl.list);
+router.get('/:id', requireAuth, ctrl.get);
+router.get('/:id/insights', requireAuth, ctrl.getInsights);
 router.post('/', requireAuth, requireRole('ADMIN'), validate('body', CreateManufacturerRequest), ctrl.create);
 router.patch('/:id', requireAuth, requireRole('ADMIN'), validate('body', UpdateManufacturerRequest), ctrl.update);
 router.delete('/:id', requireAuth, requireRole('ADMIN'), ctrl.remove);