Add webhook trigger condition for automations

Per-automation webhook URL with auto-generated 128-bit hex token.
External services (Home Assistant, IFTTT, curl) can POST to
/api/v1/webhooks/{token} with {"action": "activate"|"deactivate"}
to control automation state — no API key required (token is auth).

Backend: WebhookCondition model, engine state tracking with
immediate evaluation, webhook endpoint, schema/route updates.
Frontend: webhook option in condition editor, URL display with
copy button, card badge, i18n for en/ru/zh.

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

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

@@ -79,7 +79,7 @@ import {
 import {
     loadAutomations, openAutomationEditor, closeAutomationEditorModal,
     saveAutomationEditor, addAutomationCondition,
-    toggleAutomationEnabled, deleteAutomation,
+    toggleAutomationEnabled, deleteAutomation, copyWebhookUrl,
     expandAllAutomationSections, collapseAllAutomationSections,
 } from './features/automations.js';
 import {
@@ -311,6 +311,7 @@ Object.assign(window, {
     addAutomationCondition,
     toggleAutomationEnabled,
     deleteAutomation,
+    copyWebhookUrl,
     expandAllAutomationSections,
     collapseAllAutomationSections,