chore(i18n): drop legacy free-text country/nationality columns

Test-data only — no production migration needed (per earlier decision).
Schema is now ISO-only; readers convert ISO codes to localized names where
human-readable output is required (EOI documents, invoices, portal).

Migration 0016 drops:
  - clients.nationality
  - companies.incorporation_country
  - client_addresses.{state_province, country}
  - company_addresses.{state_province, country}

Code paths that previously read free-text values now read the ISO column
and pass through `getCountryName()` / `getSubdivisionName()` for rendering.
Document templates ({{client.nationality}}), portal client view, EOI/
reservation-agreement contexts, and invoice billing addresses all updated.

Public yacht-interest endpoint (/api/public/interests) drops the legacy
fields from its insert path and writes ISO codes only. The Zod validators
no longer accept the legacy fields — older website builds posting raw
'incorporationCountry' / 'country' / 'stateProvince' will get 400s.
Server-side phone normalization is unchanged.

Seed data updated to use ISO codes (GB/FR/ES/GR/SE/IT/GH/MC/PA), spread
across continents to keep test fixtures realistic.

Test assertions updated to match the new render shape (e.g.
'United States' not 'US', 'California' not 'CA').

Vitest: 741 -> 741 (unchanged count; assertions updated, no new tests).

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

src/lib/services/document-templates.ts

@@ -17,6 +17,7 @@ import { minioClient, buildStoragePath } from '@/lib/minio';
 import { env } from '@/lib/env';
 import { logger } from '@/lib/logger';
 import { generatePdf } from '@/lib/pdf/generate';
+import { getCountryName } from '@/lib/i18n/countries';
 import {
   createDocument as documensoCreate,
   sendDocument as documensoSend,
@@ -344,7 +345,9 @@ export async function resolveTemplate(
         tokenMap['{{client.fullName}}'] = client.fullName ?? '';
         tokenMap['{{client.email}}'] = emailContact?.value ?? '';
         tokenMap['{{client.phone}}'] = phoneContact?.value ?? '';
-        tokenMap['{{client.nationality}}'] = client.nationality ?? '';
+        tokenMap['{{client.nationality}}'] = client.nationalityIso
+          ? getCountryName(client.nationalityIso, 'en')
+          : '';
       }
     }
   }