feat: host detail page + FM host context

Add /hosts/:id detail page with unified timeline (HostEvents + FMs + Repairs
+ part arrivals/departures) and a deployed-parts table. Hosts list rows now
link to the page. FM list + detail surface inline State/Stack badges next
to the asset ID, with the asset ID linking to the host page.

HostEvent audit model added; create/update in the hosts service now diff
and log state, stack, and field changes the same way parts.ts does.

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

packages/shared/src/enums.ts

@@ -33,6 +33,14 @@ export const PartEventType = z.enum([
 ]);
 export type PartEventType = z.infer<typeof PartEventType>;
 
+export const HostEventType = z.enum([
+  'CREATED',
+  'STATE_CHANGED',
+  'STACK_CHANGED',
+  'FIELD_UPDATED',
+]);
+export type HostEventType = z.infer<typeof HostEventType>;
+
 export const FmStatus = z.enum(['OPEN', 'CLOSED']);
 export type FmStatus = z.infer<typeof FmStatus>;