fix: Wire archive button to updateInitiative mutation

The Archive menu item in InitiativeCard had no onClick handler.
Added mutation call with confirmation dialog (shift+click to skip).

packages/web/src/components/InitiativeCard.tsx

@@ -36,6 +36,21 @@ export function InitiativeCard({
   onSpawnArchitect,
   onDelete,
 }: InitiativeCardProps) {
+  const utils = trpc.useUtils();
+  const archiveMutation = trpc.updateInitiative.useMutation({
+    onSuccess: () => utils.listInitiatives.invalidate(),
+  });
+
+  function handleArchive(e: React.MouseEvent) {
+    if (
+      !e.shiftKey &&
+      !window.confirm(`Archive "${initiative.name}"?`)
+    ) {
+      return;
+    }
+    archiveMutation.mutate({ id: initiative.id, status: "archived" });
+  }
+
   // Each card fetches its own phase stats (N+1 acceptable for v1 small counts)
   const phasesQuery = trpc.listPhases.useQuery({
     initiativeId: initiative.id,
@@ -109,7 +124,7 @@ export function InitiativeCard({
               </Button>
             </DropdownMenuTrigger>
             <DropdownMenuContent align="end">
-              <DropdownMenuItem>Archive</DropdownMenuItem>
+              <DropdownMenuItem onClick={handleArchive}>Archive</DropdownMenuItem>
               <DropdownMenuSeparator />
               <DropdownMenuItem
                 className="text-destructive"