Fix federated E2EE delivery when remote node metadata exceeds key lookup limit

Hop-State: A_06FPCJKZ17TQRWHPEDC2R30
Hop-Proposal: R_06FPCJKCFSDGTQJV38RW9AG
Hop-Task: T_06FPCHWGKW3T4JFQZMN4MT8
Hop-Attempt: AT_06FPCHWGKYKYAXA04H4WRY0

src/app/api/node/key/route.test.ts

@@ -0,0 +1,31 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+
+const mocks = vi.hoisted(() => ({
+  getNodePublicKey: vi.fn(),
+}));
+
+vi.mock('@/lib/swarm/node-keys', () => ({
+  getNodePublicKey: mocks.getNodePublicKey,
+}));
+
+import { GET } from './route';
+
+describe('GET /api/node/key', () => {
+  beforeEach(() => {
+    mocks.getNodePublicKey.mockReset();
+    process.env.NEXT_PUBLIC_NODE_DOMAIN = 'node.example';
+  });
+
+  it('returns only the node identity needed for signature verification', async () => {
+    mocks.getNodePublicKey.mockResolvedValue('public-key');
+
+    const result = await GET();
+
+    expect(result.status).toBe(200);
+    expect(result.headers.get('cache-control')).toBe('no-store');
+    await expect(result.json()).resolves.toEqual({
+      domain: 'node.example',
+      publicKey: 'public-key',
+    });
+  });
+});

src/app/api/node/key/route.ts

@@ -0,0 +1,22 @@
+import { NextResponse } from 'next/server';
+
+import { getNodePublicKey } from '@/lib/swarm/node-keys';
+
+export async function GET() {
+  try {
+    const publicKey = await getNodePublicKey();
+    if (!publicKey) {
+      return NextResponse.json({ error: 'Node public key is unavailable' }, { status: 503 });
+    }
+
+    return NextResponse.json({
+      domain: process.env.NEXT_PUBLIC_NODE_DOMAIN || 'localhost:43821',
+      publicKey,
+    }, {
+      headers: { 'Cache-Control': 'no-store' },
+    });
+  } catch (error) {
+    console.error('Node public key error:', error);
+    return NextResponse.json({ error: 'Node public key is unavailable' }, { status: 503 });
+  }
+}