refactor(doura): simplify triggerEffects to only accept Dep

The ReactiveEffect[] branch in triggerEffects was inherited from
Vue 3 but never used in doura — all three call sites pass a Dep
(Set). Remove the unused union type and the isArray check.

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

Author: liximomo

packages/doura/src/reactivity/effect.ts

@@ -359,9 +359,9 @@ export function trigger(
   }
 }
 
-export function triggerEffects(dep: Dep | ReactiveEffect[]) {
+export function triggerEffects(dep: Dep) {
   // spread into array for stabilization
-  const effects = isArray(dep) ? dep : [...dep]
+  const effects = [...dep]
   for (const effect of effects) {
     if (effect.view) {
       triggerEffect(effect)