fix(components): deduplicate plugin handler registration

quartz/components/registry.ts

@@ -90,7 +90,12 @@ class ComponentRegistry {
       try {
         let instance: QuartzComponent
         if (typeof r.component === "function") {
-          instance = this.instantiate(r.component as QuartzComponentConstructor, undefined)
+          // Check if this constructor was already instantiated (with any options).
+          // Re-instantiating with `undefined` when options were provided would create
+          // a duplicate instance with separate afterDOMLoaded scripts.
+          const existing = this.findCachedInstance(r.component as QuartzComponentConstructor)
+          instance =
+            existing ?? this.instantiate(r.component as QuartzComponentConstructor, undefined)
         } else {
           instance = r.component as QuartzComponent
         }
@@ -103,6 +108,17 @@ class ComponentRegistry {
     }
     return results
   }
+
+  private findCachedInstance(
+    constructor: QuartzComponentConstructor<any>,
+  ): QuartzComponent | undefined {
+    const ctorId = (constructor as unknown as { __cacheId?: string }).__cacheId
+    if (!ctorId) return undefined
+    for (const [key, instance] of this.instanceCache) {
+      if (key.startsWith(`${ctorId}:`)) return instance
+    }
+    return undefined
+  }
 }
 
 export const componentRegistry = new ComponentRegistry()