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/lib/queryKeys.ts

@@ -73,6 +73,7 @@ export const queryKeys = {
     list: (filters?: Record<string, unknown>) =>
       [...queryKeys.partModels.all, 'list', filters ?? {}] as const,
     detail: (id: string) => [...queryKeys.partModels.all, 'detail', id] as const,
+    insights: (id: string) => [...queryKeys.partModels.all, 'insights', id] as const,
   },
   tags: {
     all: ['tags'] as const,