feat(part-models): detail page with fleet insights

Adds /part-models/:id mirroring host/part detail pattern: KPIs for
units, spend, avg price, failure counts, and FMs implicating the
model, a state-breakdown bar chart, and the parts-of-this-model
table. New GET /part-models/:id/insights aggregates via part.groupBy
+ aggregate and repair/fm counts.

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

apps/web/src/App.tsx

@@ -13,6 +13,7 @@ import PartDetail from './pages/PartDetail.js';
 import Locations from './pages/Locations.js';
 import Manufacturers from './pages/Manufacturers.js';
 import PartModels from './pages/PartModels.js';
+import PartModelDetail from './pages/PartModelDetail.js';
 import Fms from './pages/Fms.js';
 import FmDetail from './pages/FmDetail.js';
 import Repairs from './pages/Repairs.js';
@@ -60,6 +61,7 @@ export default function App() {
                     <Route path="/locations" element={<Locations />} />
                     <Route path="/manufacturers" element={<Manufacturers />} />
                     <Route path="/part-models" element={<PartModels />} />
+                    <Route path="/part-models/:id" element={<PartModelDetail />} />
                     <Route path="/fms" element={<Fms />} />
                     <Route path="/fms/:id" element={<FmDetail />} />
                     <Route path="/repairs" element={<Repairs />} />