refactor(impersonation): move user selection into action flow

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/app/(frontend)/impersonate/actions.ts

@@ -0,0 +1,48 @@
+"use server";
+
+import config from "@payload-config";
+import { isPayloadUser } from "@/utils/access-control/isPayloadUser";
+import { getPayload } from "payload";
+import { isSuperuser } from "@/utils/access-control/hasPermission";
+import { headers } from "next/headers";
+
+async function authenticate() {
+  const payloadConfig = await config;
+  const payload = await getPayload({ config: payloadConfig });
+  const hdrs = await headers();
+  const { user } = await payload.auth({
+    headers: hdrs,
+    canSetHeaders: false,
+  });
+
+  if (!isPayloadUser(user)) {
+    throw new Error("Unauthorized");
+  }
+
+  return { payload, user };
+}
+
+export async function getImpersonationUsers(): Promise<Array<{
+  id: number | string;
+  username?: string | null;
+  displayName?: string | null;
+}>> {
+  const { payload, user } = await authenticate();
+
+  if (!(await isSuperuser(payload, user))) {
+    return [];
+  }
+
+  return await payload.find({
+    collection: "users",
+    depth: 0,
+    limit: 1000,
+    pagination: false,
+    sort: "username",
+    select: {
+      username: true,
+      displayName: true,
+    },
+    overrideAccess: true,
+  }).then((result) => result.docs);
+}

src/app/(frontend)/impersonate/page.tsx

@@ -1,15 +0,0 @@
-import { redirect } from "next/navigation";
-import { getPayload } from "payload";
-import config from "@payload-config";
-import { ImpersonationControl } from "@/components/frontend/impersonation/ImpersonationControl";
-import { findImpersonationUsers } from "@/lib/impersonation";
-import { isSuperuser } from "@/utils/access-control/hasPermission";
-import { headers } from "next/headers";
-
-export default async function ImpersonatePage() {
-  const payload = await getPayload({ config });
-  const { user } = await payload.auth({ headers: await headers(), canSetHeaders: false });
-  if (!user || !(await isSuperuser(payload, user))) redirect("/");
-  const users = await findImpersonationUsers(payload);
-  return <main className="flex-1 space-y-6 p-6 md:p-8"><ImpersonationControl users={users.docs as Parameters<typeof ImpersonationControl>[0]["users"]} /></main>;
-}