feat(sdk): collect device metadata during verify handshake

Auto-collect navigator.userAgent, platform, and language in the SDK
verify RPC payload. Add DeviceMeta type. Hub receives this metadata
for display in the Desktop UI device list and confirmation dialog.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

packages/sdk/src/actions/index.ts

@@ -25,6 +25,7 @@ export {
   type DeleteAgentResult,
   type UpdateGatewayParams,
   type UpdateGatewayResult,
+  type DeviceMeta,
   type VerifyParams,
   type VerifyResult,
 } from "./rpc";

packages/sdk/src/actions/rpc.ts

@@ -146,9 +146,17 @@ export interface UpdateGatewayResult {
   connectionState: string;
 }
 
+/** Device metadata collected during verify handshake */
+export interface DeviceMeta {
+  userAgent?: string;
+  platform?: string;
+  language?: string;
+}
+
 /** verify - request params */
 export interface VerifyParams {
   token?: string;
+  meta?: DeviceMeta;
 }
 
 /** verify - response payload */

packages/sdk/src/client.ts

@@ -312,10 +312,15 @@ export class GatewayClient {
         if (this.options.hubId) {
           // Set internal state to allow send/request during verify
           this._state = "registered";
+          const meta = typeof navigator !== "undefined" ? {
+            userAgent: navigator.userAgent,
+            platform: navigator.platform,
+            language: navigator.language,
+          } : undefined;
           this.request<{ hubId: string; agentId: string }>(
             this.options.hubId,
             "verify",
-            { token: this.options.token },
+            { token: this.options.token, meta },
             this.options.verifyTimeout,
           )
             .then((result) => {