Refactored the interest-detail 404 pattern into a reusable
`<DetailNotFound>` component and applied it to the four other entity
detail pages. Pre-fix, navigating to a wrong-port or stale entity URL
silently rendered the layout shell with empty tabs on:
- /[portSlug]/clients/[id]
- /[portSlug]/yachts/[id]
- /[portSlug]/companies/[id]
- /[portSlug]/berths/[id]
All four now route a 404/403 response into an explicit "<Entity> not
found" / "No access" EmptyState with a back-to-list CTA, and the
TanStack Query retry policy short-circuits 404/403s so the empty state
appears immediately.
1373/1373 vitest pass.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>