test(vscode): guard the Emmet mapping and auto-close setting

Also fix an unused-var lint failure in completion-scope.test.js blocking the production gate.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

editors/vscode/test/completion-scope.test.js

@@ -74,7 +74,7 @@ test("provideCompletionItems returns empty array when inside view block", () =>
     getText() {
       return PAGE;
     },
-    offsetAt(position) {
+    offsetAt() {
       return PAGE.indexOf("<div");
     },
     lineAt() {
@@ -94,7 +94,7 @@ test("provideCompletionItems returns non-empty array when inside functions block
     getText() {
       return PAGE;
     },
-    offsetAt(position) {
+    offsetAt() {
       return PAGE.indexOf("function go");
     },
     lineAt() {