feat: IconGridSelect, CrossLink, SearchPalette components + entity crosslinks

New components:
- IconGridSelect: Visual grid selector replacing <select> dropdowns,
  with icon + label cells, fixed-position popup, smart placement
- CrossLink: Inline clickable badge for cross-entity navigation,
  hover highlights primary, used on entity cards
- SearchPalette: Ctrl+K global command palette, searches all entity
  types via cached data, grouped results, keyboard navigation

Integration:
- Targets: type selector uses IconGridSelect (4-column grid with icons)
- Targets: bot crosslink on telegram/email/matrix target cards
- Command Trackers: provider and config badges → CrossLinks
- Command Trackers: listener bot name → CrossLink
- Command Configs: template config shown as CrossLink on card
- Notification Trackers: provider CrossLink added to card
- Layout: SearchPalette mounted globally

Infrastructure:
- Added CommandConfig, CommandTemplateConfig, CommandTracker types
- Added notificationTrackersCache, commandTrackersCache to caches
- Added allCaches map and fetchAllCaches() for search palette
- Added searchPalette i18n keys (EN/RU)

frontend/src/routes/+layout.svelte

@@ -11,6 +11,7 @@
 	import Modal from '$lib/components/Modal.svelte';
 	import MdiIcon from '$lib/components/MdiIcon.svelte';
 	import Snackbar from '$lib/components/Snackbar.svelte';
+	import SearchPalette from '$lib/components/SearchPalette.svelte';
 	import { snackSuccess, snackError } from '$lib/stores/snackbar.svelte';
 
 	let { children } = $props();
@@ -440,6 +441,7 @@
 </Modal>
 
 <Snackbar />
+<SearchPalette />
 
 <style>
 	@media (max-width: 767px) {