fix(ui-automation): Normalize runtime labels deterministically

Use locale-insensitive lowercase normalization for runtime snapshot label filtering in both structured output and text rendering. This keeps internal target filtering deterministic across host locales.

Co-Authored-By: Codex <codex@openai.com>

Author: cameroncooke

src/utils/renderers/domain-result-text.ts

@@ -1196,7 +1196,7 @@ function compactRuntimeSnapshotText(value: string | undefined): string {
 }
 
 function normalizedRuntimeSnapshotText(value: string | undefined): string {
-  return compactRuntimeSnapshotText(value).toLocaleLowerCase();
+  return compactRuntimeSnapshotText(value).toLowerCase();
 }
 
 function isHiddenRuntimeTarget(element: RuntimeElementV1): boolean {

src/utils/structured-output-envelope.ts

@@ -106,7 +106,7 @@ function compactRuntimeSnapshotText(value: string | undefined): string {
 }
 
 function normalizedRuntimeSnapshotText(value: string | undefined): string {
-  return compactRuntimeSnapshotText(value).toLocaleLowerCase();
+  return compactRuntimeSnapshotText(value).toLowerCase();
 }
 
 function isHiddenRuntimeTarget(element: RuntimeElementV1): boolean {