fix(agent-auth): use live_view_url instead of hosted_url for login

The hosted URL was causing 404 errors. Now we fetch the live view URL
from the first poll after creating the invocation and use that instead.

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

Author: masnwilliams

cmd/agent_auth.go

@@ -120,20 +120,28 @@ func (a AgentAuthCmd) Invoke(ctx context.Context, in InvokeInput) error {
 	pterm.Println(fmt.Sprintf("  Expires: %s", invocation.ExpiresAt.Format(time.RFC3339)))
 	pterm.Println()
 
-	pterm.Info.Println("Open this URL in your browser to log in:")
-	pterm.Println()
-	pterm.Println(fmt.Sprintf("  %s", invocation.HostedURL))
-	pterm.Println()
+	// Get the live view URL from the first poll
+	state, err := a.invocations.Get(ctx, invocation.InvocationID)
+	if err != nil {
+		return util.CleanedUpSdkError{Err: err}
+	}
 
-	if !in.NoBrowser {
-		if err := browser.OpenURL(invocation.HostedURL); err != nil {
-			pterm.Warning.Printf("Could not open browser automatically: %v\n", err)
-		} else {
-			pterm.Info.Println("(Opened in browser)")
+	if state.LiveViewURL != "" {
+		pterm.Info.Println("Open this URL in your browser to log in:")
+		pterm.Println()
+		pterm.Println(fmt.Sprintf("  %s", state.LiveViewURL))
+		pterm.Println()
+
+		if !in.NoBrowser {
+			if err := browser.OpenURL(state.LiveViewURL); err != nil {
+				pterm.Warning.Printf("Could not open browser automatically: %v\n", err)
+			} else {
+				pterm.Info.Println("(Opened in browser)")
+			}
 		}
+		pterm.Println()
 	}
 
-	pterm.Println()
 	pterm.Info.Println("Polling for completion...")
 
 	startTime := time.Now()