Add notification reactive color strip source with webhook trigger

New source_type "notification" fires one-shot visual effects (flash, pulse, sweep)
triggered via POST webhook. Designed as a composite layer for overlay on persistent
sources. Includes app color mapping, whitelist/blacklist filtering, and auto-sizing.

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

server/src/wled_controller/static/js/app.js

@@ -116,6 +116,8 @@ import {
     applyGradientPreset,
     cloneColorStrip,
     copyEndpointUrl,
+    onNotificationFilterModeChange,
+    notificationAddAppColor, notificationRemoveAppColor,
 } from './features/color-strips.js';
 
 // Layer 5: audio sources
@@ -379,6 +381,8 @@ Object.assign(window, {
     applyGradientPreset,
     cloneColorStrip,
     copyEndpointUrl,
+    onNotificationFilterModeChange,
+    notificationAddAppColor, notificationRemoveAppColor,
 
     // audio sources
     showAudioSourceModal,