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/host-events.ts

@@ -0,0 +1,5 @@
+import { z } from 'zod';
+import { PaginationQuery } from './pagination.js';
+
+export const HostTimelineQuery = PaginationQuery;
+export type HostTimelineQuery = z.infer<typeof HostTimelineQuery>;