feat: add remote trust and server identity pinning

- Add SSH-style server identity keys and known-host verification for remote serve endpoints.
- Add remote add/list/remove commands for explicit endpoint persistence.
- Fix remote clients listing to fan out through target discovery instead of ambiguous auto-routing.
- Add URL glob matching for tabs filter and count with extension tests.
- Add n8n credential pinning for server public keys or SHA256 fingerprints.
- Remove obsolete compat shim behavior while keeping empty compat seams for future protocol changes.
- Bump browser-cli to 0.16.4 and n8n node to 0.3.1.
- Cover known-hosts, remote registry, compat seams, n8n protocol verification, and URL matching with tests.

n8n-nodes-browser-cli/nodes/BrowserCli/protocol.ts

@@ -24,6 +24,7 @@ import {
   createPrivateKey,
   createPublicKey,
   createHash,
+  verify as nodeVerify,
   createHmac,
   createCipheriv,
   createDecipheriv,
@@ -234,6 +235,8 @@ export interface Challenge {
   nonce?: string;
   min_client_version?: string;
   pq_kex?: { alg?: string; public_key?: string };
+  server_pubkey?: string;
+  server_sig?: string;
 }
 
 export interface AuthPayload {
@@ -247,6 +250,81 @@ function pqPublicKey(challenge: Challenge): string | null {
   return null;
 }
 
+function base64Url(buffer: Buffer): string {
+  return buffer.toString('base64').replace(/\+/g, '-').replace(/\//g, '_').replace(/=+$/g, '');
+}
+
+function ed25519PublicKeyFromHex(pubkeyHex: string): KeyObject {
+  if (!/^[0-9a-fA-F]{64}$/.test(pubkeyHex)) throw new Error('server public key must be 32-byte hex');
+  return createPublicKey({ key: { kty: 'OKP', crv: 'Ed25519', x: base64Url(Buffer.from(pubkeyHex, 'hex')) }, format: 'jwk' });
+}
+
+function signedChallenge(challenge: Challenge): Record<string, unknown> {
+  const { server_sig: _serverSig, ...rest } = challenge;
+  return rest as Record<string, unknown>;
+}
+
+export function serverFingerprint(pubkeyHex: string): string {
+  return 'SHA256:' + createHash('sha256').update(Buffer.from(pubkeyHex, 'hex')).digest('base64').replace(/=+$/g, '');
+}
+
+export function verifyServerChallengeSignature(challenge: Challenge): boolean {
+  const pubkey = challenge.server_pubkey;
+  const sig = challenge.server_sig;
+  if (!pubkey || !sig) return false;
+  try {
+    return nodeVerify(
+      null,
+      Buffer.from(canonicalJson(signedChallenge(challenge)), 'utf8'),
+      ed25519PublicKeyFromHex(pubkey),
+      Buffer.from(sig, 'hex'),
+    );
+  } catch {
+    return false;
+  }
+}
+
+export function verifyServerIdentity(
+  challenge: Challenge,
+  expectedServerIdentity: string | null | undefined,
+  endpoint: string,
+  allowUnknown: boolean,
+): void {
+  const pubkey = challenge.server_pubkey;
+  const expected = (expectedServerIdentity || '').trim();
+
+  if (!pubkey) {
+    if (expected) throw new Error(`server ${endpoint} did not advertise a server identity key`);
+    return;
+  }
+  if (!verifyServerChallengeSignature(challenge)) {
+    throw new Error(`server ${endpoint} identity signature is invalid`);
+  }
+
+  const seenFingerprint = serverFingerprint(pubkey);
+  if (!expected) {
+    if (allowUnknown) return;
+    throw new Error(
+      `Unknown browser-cli server identity for ${endpoint} (${seenFingerprint}). ` +
+        'Set the expected Server Public Key/Fingerprint in the Browser CLI credential.',
+    );
+  }
+
+  if (expected.startsWith('SHA256:')) {
+    if (expected !== seenFingerprint) {
+      throw new Error(`REMOTE SERVER IDENTITY CHANGED for ${endpoint}: expected ${expected}, seen ${seenFingerprint}`);
+    }
+    return;
+  }
+
+  const normalizedExpected = expected.toLowerCase();
+  if (normalizedExpected !== pubkey.toLowerCase()) {
+    throw new Error(
+      `REMOTE SERVER IDENTITY CHANGED for ${endpoint}: expected ${serverFingerprint(normalizedExpected)}, seen ${seenFingerprint}`,
+    );
+  }
+}
+
 /**
  * Build the single framed message a client sends in response to the challenge.
  * Mirrors `browser_cli.remote.auth.build_auth_message` + `signed_payload`.