Revert ToolName addition to Go PermissionRequest — use Extra map instead

The ToolName field doesn't exist on PermissionRequest in other SDKs.
The scenario test now reads toolName from the Extra map to stay
consistent without modifying SDK types.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: patniko

go/types.go

@@ -103,7 +103,6 @@ type SystemMessageConfig struct {
 type PermissionRequest struct {
 	Kind       string         `json:"kind"`
 	ToolCallID string         `json:"toolCallId,omitempty"`
-	ToolName   string         `json:"toolName,omitempty"`
 	Extra      map[string]any `json:"-"` // Additional fields vary by kind
 }
 

test/scenarios/callbacks/permissions/go/main.go

@@ -30,7 +30,8 @@ func main() {
 		Model: "claude-haiku-4.5",
 		OnPermissionRequest: func(req copilot.PermissionRequest, inv copilot.PermissionInvocation) (copilot.PermissionRequestResult, error) {
 			permissionLogMu.Lock()
-			permissionLog = append(permissionLog, fmt.Sprintf("approved:%s", req.ToolName))
+			toolName, _ := req.Extra["toolName"].(string)
+			permissionLog = append(permissionLog, fmt.Sprintf("approved:%s", toolName))
 			permissionLogMu.Unlock()
 			return copilot.PermissionRequestResult{Kind: "approved"}, nil
 		},