feat: parent/child company badges in client header

- Parent companies show a violet badge with subsidiary count, clickable to open modal
- Modal lists each subsidiary with policy count, task count, and claims advocate, click to navigate
- Child companies show a blue badge with parent name, clickable to navigate to parent page
- Both badges update reactively with state

ondeck/src/app/(dashboard)/clients/[id]/page.tsx

@@ -40,6 +40,7 @@ export default async function ClientDetailPage({
             id: true,
             name: true,
             _count: { select: { tasks: true, policies: true } },
+            claimsAdvocate: { select: { id: true, displayName: true, email: true } },
           },
           orderBy: { name: 'asc' },
         },

ondeck/src/components/clients/client-detail.tsx

@@ -6,6 +6,12 @@ import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card'
 import { Badge } from '@/components/ui/badge'
 import { Button } from '@/components/ui/button'
 import { Tabs, TabsContent, TabsList, TabsTrigger } from '@/components/ui/tabs'
+import {
+  Dialog,
+  DialogContent,
+  DialogHeader,
+  DialogTitle,
+} from '@/components/ui/dialog'
 import {
   Select,
   SelectContent,
@@ -14,7 +20,7 @@ import {
   SelectValue,
 } from '@/components/ui/select'
 import { Textarea } from '@/components/ui/textarea'
-import { Building2, MapPin, Phone, Mail, FileText, CheckSquare, CalendarRange, Users, X, Plus, UserCheck, StickyNote, Pencil, Trash2, ChevronDown, ChevronUp, ArrowUp, ArrowDown, ArrowUpDown } from 'lucide-react'
+import { Building2, MapPin, Phone, Mail, FileText, CheckSquare, CalendarRange, Users, X, Plus, UserCheck, StickyNote, Pencil, Trash2, ChevronDown, ChevronUp, ArrowUp, ArrowDown, ArrowUpDown, GitBranch, ChevronRight } from 'lucide-react'
 import { Combobox } from '@/components/ui/combobox'
 import { formatDate, formatRenewalDate } from '@/lib/utils'
 import { PolicyGroupManager } from '@/components/clients/policy-group-manager'
@@ -53,6 +59,7 @@ export function ClientDetail({ client, designations, policyGroups = [], allPolic
   const [parentOptions, setParentOptions] = useState<{id:string;name:string}[]>([])
   const [parentLinking, setParentLinking] = useState(false)
   const [showArchivedTasks, setShowArchivedTasks] = useState(false)
+  const [subsidiariesModalOpen, setSubsidiariesModalOpen] = useState(false)
   const [taskSort, setTaskSort] = useState<'date' | 'priority'>('date')
   const [taskSortDir, setTaskSortDir] = useState<'asc' | 'desc'>('asc')
   const [showCompleted, setShowCompleted] = useState(false)
@@ -290,6 +297,9 @@ export function ClientDetail({ client, designations, policyGroups = [], allPolic
     }
   }
 
+  const isParent = subsidiaries.length > 0
+  const isChild = !!parentClient
+
   return (
     <div className="space-y-6">
       {/* Header */}
@@ -299,7 +309,7 @@ export function ClientDetail({ client, designations, policyGroups = [], allPolic
             <Building2 className="h-8 w-8" />
             {client.name}
           </h1>
-          <div className="flex gap-4 mt-3 text-sm text-muted-foreground">
+          <div className="flex flex-wrap gap-4 mt-3 text-sm text-muted-foreground">
             {client.city && client.state && (
               <div className="flex items-center gap-1">
                 <MapPin className="h-4 w-4" />
@@ -319,9 +329,73 @@ export function ClientDetail({ client, designations, policyGroups = [], allPolic
               </div>
             )}
           </div>
+
+          {/* Parent / Child badges */}
+          <div className="flex flex-wrap gap-2 mt-3">
+            {isParent && (
+              <button
+                onClick={() => setSubsidiariesModalOpen(true)}
+                className="inline-flex items-center gap-1.5 rounded-full border border-violet-500/40 bg-violet-500/10 px-3 py-1 text-xs font-medium text-violet-700 dark:text-violet-400 hover:bg-violet-500/20 transition-colors"
+              >
+                <GitBranch className="h-3.5 w-3.5" />
+                Parent Company · {subsidiaries.length} {subsidiaries.length === 1 ? 'subsidiary' : 'subsidiaries'}
+              </button>
+            )}
+            {isChild && (
+              <Link
+                href={`/clients/${parentClient!.id}`}
+                className="inline-flex items-center gap-1.5 rounded-full border border-blue-500/40 bg-blue-500/10 px-3 py-1 text-xs font-medium text-blue-700 dark:text-blue-400 hover:bg-blue-500/20 transition-colors"
+              >
+                <ChevronRight className="h-3.5 w-3.5 rotate-180" />
+                Child of {parentClient!.name}
+              </Link>
+            )}
+          </div>
         </div>
       </div>
 
+      {/* Subsidiaries modal */}
+      <Dialog open={subsidiariesModalOpen} onOpenChange={setSubsidiariesModalOpen}>
+        <DialogContent className="sm:max-w-lg">
+          <DialogHeader>
+            <DialogTitle className="flex items-center gap-2">
+              <GitBranch className="h-5 w-5" />
+              Subsidiaries of {client.name}
+            </DialogTitle>
+          </DialogHeader>
+          <div className="space-y-2 max-h-[60vh] overflow-y-auto pr-1">
+            {subsidiaries.map((sub: any) => (
+              <Link
+                key={sub.id}
+                href={`/clients/${sub.id}`}
+                onClick={() => setSubsidiariesModalOpen(false)}
+                className="flex items-center justify-between rounded-lg border border-border p-3 hover:bg-muted/50 transition-colors group"
+              >
+                <div className="flex-1 min-w-0">
+                  <p className="font-medium text-sm group-hover:text-primary transition-colors truncate">{sub.name}</p>
+                  {sub.claimsAdvocate && (
+                    <p className="text-xs text-muted-foreground mt-0.5">
+                      Advocate: {sub.claimsAdvocate.displayName || sub.claimsAdvocate.email}
+                    </p>
+                  )}
+                </div>
+                <div className="flex items-center gap-3 ml-4 shrink-0 text-xs text-muted-foreground">
+                  <span className="flex items-center gap-1">
+                    <FileText className="h-3.5 w-3.5" />
+                    {sub._count?.policies ?? 0}
+                  </span>
+                  <span className="flex items-center gap-1">
+                    <CheckSquare className="h-3.5 w-3.5" />
+                    {sub._count?.tasks ?? 0}
+                  </span>
+                  <ChevronRight className="h-4 w-4 opacity-40 group-hover:opacity-100 transition-opacity" />
+                </div>
+              </Link>
+            ))}
+          </div>
+        </DialogContent>
+      </Dialog>
+
       {/* Client Notes — collapsible */}
       <div className="rounded-lg border bg-card">
         <button