feat(addresses): full CRUD UI for client + company multi-address

Client and company detail pages each gain an Addresses tab with click-to-edit
fields wired to the existing CountryCombobox/SubdivisionCombobox primitives.
Adds a primary toggle that demotes the previous primary inside one transaction
so the partial unique index never trips.

- New service helpers: list/add/update/remove ClientAddress + CompanyAddress
- New routes: /api/v1/clients/[id]/addresses[/addressId], same under companies/
- New shared component: <AddressesEditor> reused by both detail surfaces
- Integration tests cover happy path, primary demotion, and tenant scoping

Tests: 747/747 vitest (was 741, +6 address tests).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/clients/client-detail.tsx

@@ -7,6 +7,7 @@ import { ClientDetailHeader } from '@/components/clients/client-detail-header';
 import { getClientTabs } from '@/components/clients/client-tabs';
 import { useRealtimeInvalidation } from '@/hooks/use-realtime-invalidation';
 import { apiFetch } from '@/lib/api/client';
+import type { Address } from '@/components/shared/addresses-editor';
 
 interface ClientData {
   id: string;
@@ -64,6 +65,7 @@ interface ClientData {
     tenureType: string;
     status: string;
   }>;
+  addresses: Address[];
 }
 
 interface ClientDetailProps {