feat: token auto-refresh, studio→render wiring, admin panel (nodes + render queue)

Token auto-refresh (middleware):
- Proactively refresh fr_access when < 120s remain — no more silent 15-min kick
- Inlines /v1/auth/refresh call in middleware, stamps new cookies on response
- /admin/* protected: is_admin JWT claim required, else redirect /dashboard
- apiFetch() (src/lib/api/fetch.ts): client-side 401 → auto-refresh → retry;
  de-duplicates concurrent refresh calls; redirects to /auth on failure

Studio → Render V2 wiring:
- scenes[] no longer sent to POST /api/render (V2 render-svc fetches project
  from Studio service via saved_project_id directly)
- renderRequestSchema.scenes is now optional
- RenderModal uses apiFetch for auto-refresh on 401 during polling

Admin panel (/admin/*):
- Admin layout: server-side is_admin guard + top nav (Nodes, Render Queue)
- /admin/nodes: lists all nodes from GET /v1/nodes with status badges,
  heartbeat age, slot usage, tags; Drain (PATCH status=Draining) + Release actions
- /admin/renders: render job table with step filter tabs; progress bars,
  error messages, Retry + Cancel per-row actions; polls GET /v1/renders
- API proxy routes: /api/admin/nodes/:id/drain|release,
  /api/admin/renders/:id/retry|cancel — all validate is_admin in JWT before proxying

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

src/app/[locale]/admin/layout.tsx

@@ -0,0 +1,44 @@
+import { redirect } from "next/navigation";
+
+import { getCurrentUser } from "@/lib/auth/session";
+
+export const dynamic = "force-dynamic";
+
+export default async function AdminLayout({
+  children,
+}: {
+  children: React.ReactNode;
+}) {
+  const user = await getCurrentUser();
+  if (!user || !user.is_admin) {
+    redirect("/dashboard");
+  }
+  return (
+    <div className="min-h-screen bg-[#0c0e1a] text-gray-200">
+      <nav className="border-b border-[#1e2235] bg-[#0f1120] px-6 py-3">
+        <div className="mx-auto flex max-w-7xl items-center gap-6">
+          <span className="text-sm font-semibold text-white">FlatRender Admin</span>
+          <a
+            href="/admin/nodes"
+            className="text-sm text-gray-400 hover:text-white transition-colors"
+          >
+            Nodes
+          </a>
+          <a
+            href="/admin/renders"
+            className="text-sm text-gray-400 hover:text-white transition-colors"
+          >
+            Render Queue
+          </a>
+          <a
+            href="/dashboard"
+            className="ml-auto text-xs text-gray-500 hover:text-gray-300 transition-colors"
+          >
+            ← Back to Dashboard
+          </a>
+        </div>
+      </nav>
+      <main className="mx-auto max-w-7xl px-6 py-8">{children}</main>
+    </div>
+  );
+}

src/app/[locale]/admin/nodes/page.tsx

@@ -0,0 +1,41 @@
+import { adminGet } from "@/lib/api/admin-gateway";
+import { NodesTable } from "@/components/admin/NodesTable";
+
+export const dynamic = "force-dynamic";
+export const revalidate = 0;
+
+interface V2Node {
+  id: string;
+  name: string;
+  status: "Online" | "Busy" | "Offline" | "Draining";
+  last_heartbeat: string;
+  active_job_id: string | null;
+  slots_total: number;
+  slots_used: number;
+  version: string | null;
+  tags: string[] | null;
+}
+
+interface V2NodeList {
+  items: V2Node[];
+  total: number;
+}
+
+export default async function AdminNodesPage() {
+  const data = await adminGet<V2NodeList>("/v1/nodes?pageSize=100");
+  const nodes = data?.items ?? [];
+
+  return (
+    <div className="space-y-6">
+      <div className="flex items-center justify-between">
+        <div>
+          <h1 className="text-xl font-semibold text-white">Render Nodes</h1>
+          <p className="mt-1 text-sm text-gray-500">
+            {nodes.length} node{nodes.length !== 1 ? "s" : ""} registered
+          </p>
+        </div>
+      </div>
+      <NodesTable nodes={nodes} />
+    </div>
+  );
+}

src/app/[locale]/admin/page.tsx

@@ -0,0 +1,5 @@
+import { redirect } from "next/navigation";
+
+export default function AdminRootPage() {
+  redirect("/admin/nodes");
+}

src/app/[locale]/admin/renders/page.tsx

@@ -0,0 +1,80 @@
+import { adminGet } from "@/lib/api/admin-gateway";
+import { RenderQueueTable } from "@/components/admin/RenderQueueTable";
+
+export const dynamic = "force-dynamic";
+export const revalidate = 0;
+
+export type V2RenderJob = {
+  id: string;
+  saved_project_id: string;
+  user_id: string;
+  status: string;
+  step: string;
+  progress: number;
+  quality: string;
+  resolution: string;
+  frame_rate: number;
+  node_id: string | null;
+  error_message: string | null;
+  created_at: string;
+  updated_at: string;
+};
+
+interface V2RenderList {
+  items: V2RenderJob[];
+  total: number;
+}
+
+export default async function AdminRendersPage({
+  searchParams,
+}: {
+  searchParams: { step?: string };
+}) {
+  const step = searchParams.step ?? "";
+  const qs = step ? `?step=${step}&pageSize=50` : "?pageSize=50";
+  const data = await adminGet<V2RenderList>(`/v1/renders${qs}`);
+  const jobs = data?.items ?? [];
+  const total = data?.total ?? 0;
+
+  const steps = ["Queued", "Preparing", "Rendering", "Uploading", "Done", "Failed", "Cancelled"];
+
+  return (
+    <div className="space-y-6">
+      <div className="flex items-center justify-between">
+        <div>
+          <h1 className="text-xl font-semibold text-white">Render Queue</h1>
+          <p className="mt-1 text-sm text-gray-500">{total} total jobs</p>
+        </div>
+      </div>
+
+      {/* Step filter tabs */}
+      <div className="flex gap-2 flex-wrap">
+        <a
+          href="/admin/renders"
+          className={`rounded-full border px-3 py-1 text-xs font-medium transition-colors ${
+            !step
+              ? "border-primary-500 bg-primary-600/20 text-white"
+              : "border-[#1e2235] text-gray-400 hover:text-white hover:border-[#2a3050]"
+          }`}
+        >
+          All
+        </a>
+        {steps.map((s) => (
+          <a
+            key={s}
+            href={`/admin/renders?step=${s}`}
+            className={`rounded-full border px-3 py-1 text-xs font-medium transition-colors ${
+              step === s
+                ? "border-primary-500 bg-primary-600/20 text-white"
+                : "border-[#1e2235] text-gray-400 hover:text-white hover:border-[#2a3050]"
+            }`}
+          >
+            {s}
+          </a>
+        ))}
+      </div>
+
+      <RenderQueueTable jobs={jobs} />
+    </div>
+  );
+}