feat: grouped nav tree with badges, dashboard events section with filtered chart

Navigation:
- Restructure flat nav into grouped tree: Notification (Trackers,
  Configs, Templates), Commands (same), Bots (Telegram), Settings
  (Common, Users)
- Collapsible groups with expand/collapse state persisted in localStorage
- Auto-expand group containing the active page
- Counter badges on groups (sum of children) and individual items
- New /api/status/counts endpoint for nav badge data
- Mobile bottom nav uses flattened key pages

Dashboard:
- Rename "Recent Events" to "Events"
- Move chart under Events section (after filters, before event list)
- Filters (event type, provider, search) now affect both the event
  list AND the chart simultaneously
- Add event_type, provider_id, search filter params to /api/status/chart

frontend/src/routes/+page.svelte

@@ -34,8 +34,8 @@
 	/** Calculate how many event rows fit in the remaining viewport space. */
 	function calcPageSize(): number {
 		if (typeof window === 'undefined') return 8;
-		const EVENT_ROW_HEIGHT = 50; // px per event row (content + gap)
-		const FIXED_OVERHEAD = 600; // header + stats + chart + events header + filters + paginator + padding
+		const EVENT_ROW_HEIGHT = 50;
+		const FIXED_OVERHEAD = 700; // slightly more for chart in Events section
 		const available = window.innerHeight - FIXED_OVERHEAD;
 		return Math.max(3, Math.floor(available / EVENT_ROW_HEIGHT));
 	}
@@ -53,13 +53,19 @@
 		requestAnimationFrame(frame);
 	}
 
+	/** Build filter query string (shared by events list + chart). */
+	function buildFilterParams(): URLSearchParams {
+		const params = new URLSearchParams();
+		if (filterEventType) params.set('event_type', filterEventType);
+		if (filterProviderId) params.set('provider_id', filterProviderId);
+		if (filterSearch) params.set('search', filterSearch);
+		return params;
+	}
+
 	async function loadEvents() {
 		eventsLoading = true;
 		try {
-			const params = new URLSearchParams();
-			if (filterEventType) params.set('event_type', filterEventType);
-			if (filterProviderId) params.set('provider_id', filterProviderId);
-			if (filterSearch) params.set('search', filterSearch);
+			const params = buildFilterParams();
 			params.set('sort', filterSort);
 			params.set('limit', String(eventsLimit));
 			params.set('offset', String(eventsOffset));
@@ -72,9 +78,19 @@
 		}
 	}
 
+	async function loadChart() {
+		try {
+			const params = buildFilterParams();
+			const qs = params.toString();
+			const chartRes = await api<any>(`/status/chart${qs ? '?' + qs : ''}`);
+			chartDays = chartRes.days || [];
+		} catch {}
+	}
+
 	function applyFilters() {
 		eventsOffset = 0;
 		loadEvents();
+		loadChart();
 	}
 
 	function goToPage(page: number) {
@@ -216,8 +232,7 @@
 		{/each}
 	</div>
 
-	<EventChart days={chartDays} />
-
+	<!-- Events section -->
 	<h3 class="text-base font-semibold mb-3 flex items-center gap-2">
 		<MdiIcon name="mdiPulse" size={18} />
 		{t('dashboard.recentEvents')}
@@ -253,6 +268,9 @@
 		</select>
 	</div>
 
+	<!-- Chart (now inside Events section, affected by filters) -->
+	<EventChart days={chartDays} />
+
 	{#if eventsLoading}
 		<Card><p class="text-sm text-center py-4" style="color: var(--color-muted-foreground);">{t('dashboard.loadingEvents')}</p></Card>
 	{:else if status.recent_events.length === 0}