feat: Phases 4-7 — Full Feature Expansion (26 features)

Phase 4 — New Widget Types:
- Clock/Weather, System Stats, RSS/Feed, Calendar, Markdown,
  Metric/Counter, Link Group, Camera/Stream widgets
- Backend services with caching for each data source
- Full creation form with dynamic config fields per type

Phase 5 — Visual & Styling Enhancements:
- Glassmorphism card style (solid/glass/outline)
- Board-level themes with per-board hue/saturation
- Animated SVG status rings replacing static dots
- Card size options (compact/medium/large)
- Custom CSS injection (admin + per-board, sanitized)
- Wallpaper backgrounds with blur/overlay/parallax

Phase 6 — Functional Features:
- Favorites bar with drag-and-drop reordering
- Recent apps tracking with privacy toggle
- Uptime dashboard page (/status, guest-accessible)
- Notifications system (Discord/Slack/Telegram/HTTP webhooks)
- App tags with filtering in board view
- Multi-URL app cards with expandable sub-links
- Personal API tokens with scoped permissions
- Audit log with retention and admin viewer

Phase 7 — Quality of Life:
- Onboarding wizard (5-step first-launch setup)
- App URL health preview with favicon/title detection
- Board templates (4 built-in + custom import/export)
- Keyboard shortcut overlay (j/k nav, 1-9 boards, ? help)

212 files changed, 15641 insertions, 980 deletions.
Build, lint, type check, and 222 tests all pass.

src/lib/components/app/AppForm.svelte

@@ -4,6 +4,7 @@
 	import type { z } from 'zod';
 	import type { createAppSchema } from '$lib/utils/validators.js';
 	import AppIconPicker from './AppIconPicker.svelte';
+	import AppUrlPreview from './AppUrlPreview.svelte';
 	import IconGrid from '$lib/components/ui/IconGrid.svelte';
 	import type { IconGridItem } from '$lib/components/ui/IconGrid.svelte';
 
@@ -65,6 +66,20 @@
 		</div>
 	</div>
 
+	<!-- URL Preview / Test Connection -->
+	<AppUrlPreview
+		url={$form.url ?? ''}
+		currentIcon={$form.icon ?? ''}
+		currentName={$form.name ?? ''}
+		onApplyFavicon={(favicon) => {
+			$form.icon = favicon;
+			$form.iconType = 'url';
+		}}
+		onApplyTitle={(title) => {
+			$form.name = title;
+		}}
+	/>
+
 	<div>
 		<label for="description" class="mb-1 block text-sm font-medium text-card-foreground">
 			{$t('app.description')}