fix(config-cache): has() no longer inflates hit/miss stats

has() delegated to get(), which increments this.hits or this.misses.
The common has()+get() pattern double-counted every lookup.

Re-implement has() with its own TTL check so cache statistics stay
accurate.

35 unit tests added including 3 regression tests for this fix.

Closes #497

Author: nikolasdehor

.aios-core/core/config/config-cache.js

@@ -72,7 +72,17 @@ class ConfigCache {
    * @returns {boolean} True if key exists and is valid
    */
   has(key) {
-    return this.get(key) !== null;
+    // Check directly instead of delegating to get(), which would
+    // increment hits/misses and inflate cache statistics (fixes #497)
+    if (!this.cache.has(key)) return false;
+
+    const timestamp = this.timestamps.get(key);
+    if (Date.now() - timestamp > this.ttl) {
+      this.cache.delete(key);
+      this.timestamps.delete(key);
+      return false;
+    }
+    return true;
   }
 
   /**