perf(rule): resolve rule results synchronously instead of via setTimeout(0)

The setTimeout(0) wrapper around resolve(ruleResult) created 335 macrotask
transitions per scan. On large DOMs with advance ON, these interleave with
concurrent DevTools IPC calls (resource.getContent), inflating axe.run
from ~14s to ~85s. Resolving synchronously eliminates the contention.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: chikara1608

lib/core/base/rule.js

@@ -310,11 +310,10 @@ Rule.prototype.run = function run(context, options = {}, resolve, reject) {
     if (options.performanceTimer) {
       this._logRulePerformance();
     }
-    // Defer the rule's execution to prevent "unresponsive script" warnings.
-    // See https://github.com/dequelabs/axe-core/pull/1172 for discussion and details.
-    setTimeout(() => {
-      resolve(ruleResult);
-    }, 0);
+    // [a11y-core]: resolve synchronously — the setTimeout(0) caused 335
+    // macrotask transitions that interleave with DevTools IPC (resource.getContent),
+    // inflating axe.run from ~14s to ~85s on large DOMs with advance ON.
+    resolve(ruleResult);
   }).catch(error => {
     if (options.performanceTimer) {
       this._logRulePerformance();