feat(helpdesk): add dashboards, communication feed, settings UI and fix routing

Add support/sales/controlling dashboards with KPIs, trend charts and
risk indicators. Add debitor communication timeline, contact filters,
system recommendations engine, and configurable controlling risk rules.

Rename search→index to fix query-string preservation on back navigation.
Remove fake escalation rate metric, add KPI info tooltips, and switch
trend chart colors to red (created) / green (closed) for clarity.

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

modules/helpdesk/web/js/helpdesk-ticket.js

@@ -9,6 +9,7 @@ import {
   renderCommunicationFeed,
   renderCommunicationHint,
 } from './helpdesk-communication.js';
+import { renderEmptyState } from './helpdesk-empty-state.js';
 
 const container = document.querySelector('.app-details-container[data-ticket-no]');
 if (container) {
@@ -95,9 +96,12 @@ function init(container) {
 
   function renderTimeline(entries) {
     if (entries.length === 0) {
-      return `<div class="app-empty-state app-empty-state-compact">
-        <p class="app-empty-state-message">${esc(t('No activity found.'))}</p>
-      </div>`;
+      return renderEmptyState({
+        message: t('No activity found.'),
+        size: 'compact',
+        align: 'center',
+        icon: false,
+      });
     }
 
     let html = '<div class="helpdesk-timeline">';