fix: importer foundry.applications.api et utiliser _onRender dans les pickers AppV2

- applications.mjs: import HandlebarsApplicationMixin/ApplicationV2 from
  foundry.applications.api (they are not globals in Foundry v14), fixing
  'ReferenceError: HandlebarsApplicationMixin is not defined'
- Replace activateListeners(html) with _onRender(context, options) and
  this.element — AppV2 does not call activateListeners
- TraitSelector: remove recursive render(true) in _validateTraits
- fight.mjs: VermineCombatTracker same _onRender conversion

module/system/fight.mjs

@@ -239,9 +239,9 @@ export class VermineCombatTracker extends foundry.applications.sidebar.tabs.Comb
     return context;
   }
 
-  activateListeners(html) {
-    super.activateListeners(html);
-    html.querySelectorAll("[data-attitude]").forEach(el => {
+  _onRender(context, options) {
+    super._onRender(context, options);
+    this.element.querySelectorAll("[data-attitude]").forEach(el => {
       el.addEventListener("click", this._setStatut.bind(this));
     });
   }