refactor(clients): rebuild detail tabs + columns for new data model

- ClientData in client-detail.tsx now reflects the stripped shape from
  Task 8.2 (drop companyName/isProxy/proxy*/yacht*/berthSizeDesired) and
  gains yachts / companies / activeReservations arrays.
- client-tabs.tsx: Overview trimmed (personal, contacts, source, tags);
  three new count-badged tabs (Yachts, Companies, Reservations).
- New client-yachts-tab.tsx renders owned yachts + Add yacht CTA (TODO:
  YachtForm preset-owner wiring for v2).
- New client-companies-tab.tsx renders memberships with Primary badge and
  since-date; management still lives on the company detail page.
- New client-reservations-tab.tsx maps activeReservations into ReservationRow
  shape and delegates to <ReservationList showBerth />.
- client-columns.tsx drops companyName column (TODO: add Yachts count +
  Primary company once list endpoint joins those).
- client-filters.tsx drops isProxy filter.
- Wire realtime invalidations for yacht:ownership_transferred,
  company_membership:added/ended, and berth_reservation:*.

src/components/clients/client-companies-tab.tsx

@@ -0,0 +1,103 @@
+'use client';
+
+import Link from 'next/link';
+import { useParams } from 'next/navigation';
+import { format } from 'date-fns';
+
+import {
+  Table,
+  TableHeader,
+  TableBody,
+  TableCell,
+  TableHead,
+  TableRow,
+} from '@/components/ui/table';
+import { Badge } from '@/components/ui/badge';
+import { EmptyState } from '@/components/shared/empty-state';
+
+interface ClientCompaniesTabProps {
+  clientId: string;
+  companies: Array<{
+    membershipId: string;
+    role: string;
+    isPrimary: boolean;
+    startDate: string | Date;
+    company: {
+      id: string;
+      name: string;
+      legalName: string | null;
+      status: string;
+    };
+  }>;
+}
+
+function formatSince(startDate: string | Date): string {
+  const d = typeof startDate === 'string' ? new Date(startDate) : startDate;
+  if (Number.isNaN(d.getTime())) return '—';
+  return format(d, 'MMM d, yyyy');
+}
+
+export function ClientCompaniesTab({ clientId: _clientId, companies }: ClientCompaniesTabProps) {
+  const routeParams = useParams<{ portSlug: string }>();
+  const portSlug = routeParams?.portSlug ?? '';
+
+  if (companies.length === 0) {
+    return (
+      <EmptyState
+        title="No company memberships"
+        description="This client is not affiliated with any companies yet. Add a membership from a company's detail page."
+      />
+    );
+  }
+
+  return (
+    <div className="space-y-4">
+      <h3 className="text-sm font-medium">Company affiliations</h3>
+      <div className="rounded-md border">
+        <Table>
+          <TableHeader>
+            <TableRow>
+              <TableHead>Company</TableHead>
+              <TableHead>Role</TableHead>
+              <TableHead>Primary</TableHead>
+              <TableHead>Since</TableHead>
+            </TableRow>
+          </TableHeader>
+          <TableBody>
+            {companies.map((m) => (
+              <TableRow key={m.membershipId}>
+                <TableCell>
+                  <Link
+                    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+                    href={`/${portSlug}/companies/${m.company.id}` as any}
+                    className="text-primary hover:underline"
+                  >
+                    {m.company.name}
+                  </Link>
+                  {m.company.legalName && (
+                    <span className="ml-2 text-xs text-muted-foreground">
+                      ({m.company.legalName})
+                    </span>
+                  )}
+                </TableCell>
+                <TableCell className="capitalize">{m.role.replace('_', ' ')}</TableCell>
+                <TableCell>
+                  {m.isPrimary ? (
+                    <Badge variant="secondary" className="text-xs">
+                      Primary
+                    </Badge>
+                  ) : (
+                    <span className="text-muted-foreground">—</span>
+                  )}
+                </TableCell>
+                <TableCell className="text-muted-foreground text-sm">
+                  {formatSince(m.startDate)}
+                </TableCell>
+              </TableRow>
+            ))}
+          </TableBody>
+        </Table>
+      </div>
+    </div>
+  );
+}