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/web/src/App.tsx

@@ -12,6 +12,7 @@ import Parts from './pages/Parts.js';
 import PartDetail from './pages/PartDetail.js';
 import Locations from './pages/Locations.js';
 import Manufacturers from './pages/Manufacturers.js';
+import ManufacturerDetail from './pages/ManufacturerDetail.js';
 import PartModels from './pages/PartModels.js';
 import PartModelDetail from './pages/PartModelDetail.js';
 import Fms from './pages/Fms.js';
@@ -60,6 +61,7 @@ export default function App() {
                     <Route path="/parts/:id" element={<PartDetail />} />
                     <Route path="/locations" element={<Locations />} />
                     <Route path="/manufacturers" element={<Manufacturers />} />
+                    <Route path="/manufacturers/:id" element={<ManufacturerDetail />} />
                     <Route path="/part-models" element={<PartModels />} />
                     <Route path="/part-models/:id" element={<PartModelDetail />} />
                     <Route path="/fms" element={<Fms />} />