Add tooltip hints to form fields, fix navigation overlap bug

- Create Hint component with fixed-position floating tooltip
- Add hints to tracking configs (periodic/scheduled/memory modes,
  favorites, times, album mode, rating), template configs (section
  legends), targets (AI captions, media settings, config selectors),
  and trackers (scan interval)
- Add 21 hint i18n keys in EN and RU
- Fix transition:slide → in:slide on all pages to prevent content
  overlap when navigating away mid-animation
- Merge Asset Display into Event Tracking fieldset; use consistent
  "Max Assets" label with hint in each section

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/routes/trackers/+page.svelte

@@ -9,6 +9,7 @@
 	import IconPicker from '$lib/components/IconPicker.svelte';
 	import MdiIcon from '$lib/components/MdiIcon.svelte';
 	import ConfirmModal from '$lib/components/ConfirmModal.svelte';
+	import Hint from '$lib/components/Hint.svelte';
 
 	let loaded = $state(false);
 	let loadError = $state('');
@@ -136,7 +137,7 @@
 		</button>
 	</Card>
 {:else if showForm}
-	<div transition:slide={{ duration: 200 }}>
+	<div in:slide={{ duration: 200 }}>
 	<Card class="mb-6">
 		{#if error}<div class="bg-[var(--color-error-bg)] text-[var(--color-error-fg)] text-sm rounded-md p-3 mb-4">{error}</div>{/if}
 		<form onsubmit={save} class="space-y-4">
@@ -175,7 +176,7 @@
 				</div>
 			{/if}
 			<div>
-				<label for="trk-interval" class="block text-sm font-medium mb-1">{t('trackers.scanInterval')}</label>
+				<label for="trk-interval" class="block text-sm font-medium mb-1">{t('trackers.scanInterval')}<Hint text={t('hints.scanInterval')} /></label>
 				<input id="trk-interval" type="number" bind:value={form.scan_interval} min="10" max="3600" class="w-32 px-3 py-2 border border-[var(--color-border)] rounded-md text-sm bg-[var(--color-background)]" />
 			</div>