feat(invites): add cancel button to revoke pending invites

- New DELETE /api/invites/[id] endpoint — only the owning family can delete
- Settings page shows expiry date on each pending invite
- Cancel button removes invite instantly from list (optimistic UI)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/api/invites/[id]/route.ts

@@ -0,0 +1,26 @@
+import { NextResponse } from "next/server";
+import { sql } from "@/db";
+import { requireFamily } from "@/lib/auth";
+
+// DELETE — cancel/revoke a pending invite (only the family that sent it can delete it)
+export async function DELETE(
+  _req: Request,
+  { params }: { params: Promise<{ id: string }> }
+) {
+  const auth = await requireFamily();
+  if (!auth.success) return NextResponse.json({ error: auth.error }, { status: auth.status });
+
+  const { id } = await params;
+
+  try {
+    const result = await sql.unsafe(
+      `DELETE FROM family_invites WHERE id = $1 AND family_id = $2`,
+      [id, auth.session!.familyId]
+    );
+    // result.count === 0 means the invite didn't belong to this family or didn't exist
+    return NextResponse.json({ success: true });
+  } catch (error) {
+    console.error(error);
+    return NextResponse.json({ error: String(error) }, { status: 500 });
+  }
+}

src/app/settings/page.tsx

@@ -123,6 +123,15 @@ export default function SettingsPage() {
     }
   };
 
+  const deleteInvite = async (inviteId: string) => {
+    try {
+      await fetch(`/api/invites/${inviteId}`, { method: "DELETE" });
+      setInvites(prev => prev.filter(i => i.id !== inviteId));
+    } catch (err) {
+      console.error("Failed to delete invite:", err);
+    }
+  };
+
   const sendInvite = async () => {
     if (!inviteEmail || !familyId) return;
     setInviteLoading(true);
@@ -273,9 +282,18 @@ export default function SettingsPage() {
                 <div className="mb-3">
                   <div className="text-sm text-gray-500 mb-2">Pending Invites</div>
                   {invites.map((invite) => (
-                    <div key={invite.id} className="flex justify-between items-center p-2 bg-gray-50 rounded text-sm">
-                      <span>{invite.email}</span>
-                      <span className="text-gray-400">Pending</span>
+                    <div key={invite.id} className="flex justify-between items-center p-2 bg-gray-50 dark:bg-gray-700 rounded text-sm mb-1">
+                      <div>
+                        <div className="font-medium text-gray-800 dark:text-gray-100">{invite.email}</div>
+                        <div className="text-xs text-gray-400">Pending · expires {new Date(invite.expiresAt).toLocaleDateString()}</div>
+                      </div>
+                      <button
+                        onClick={() => deleteInvite(invite.id)}
+                        className="text-xs text-red-400 hover:text-red-600 dark:hover:text-red-300 px-2 py-1 rounded hover:bg-red-50 dark:hover:bg-red-900/20 transition-colors"
+                        title="Cancel invite"
+                      >
+                        Cancel
+                      </button>
                     </div>
                   ))}
                 </div>