refactor(clients): strip yacht/company/proxy fields from validator

Remove deprecated companyName, isProxy, proxyType, actualOwnerName, yacht
dimensions, and berthSizeDesired fields from createClientSchema and the
isProxy filter from listClientsSchema. First step of PR 8; cascading TS
errors in clients.service.ts and client-form.tsx are addressed in 8.2/8.3.

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

tests/unit/validators.test.ts

@@ -62,12 +62,19 @@ describe('createClientSchema', () => {
   it('accepts optional fields', () => {
     const result = createClientSchema.safeParse({
       ...validClient,
-      companyName: 'ACME',
       nationality: 'AU',
       source: 'manual' as const,
     });
     expect(result.success).toBe(true);
   });
+
+  it('accepts minimal valid input (no deprecated yacht/company fields)', () => {
+    const result = createClientSchema.safeParse({
+      fullName: 'Alice',
+      contacts: [{ channel: 'email', value: 'a@example.com' }],
+    });
+    expect(result.success).toBe(true);
+  });
 });
 
 describe('updateClientSchema (partial)', () => {