feat: locale-aware command templates, debounced auto-sync, entity pickers

- Locale-aware templates: CommandTemplateSlot now has a locale column,
  allowing each slot to have per-language variants (EN/RU). Templates
  are resolved at runtime from the Telegram user's language_code.

- Merged system configs: "Default Commands (EN)" and "(RU)" merged
  into a single "Default Commands" config with locale-aware slots.
  Migration handles existing data automatically.

- Configurable command descriptions: hardcoded COMMAND_DESCRIPTIONS
  replaced with desc_* template slots (desc_status, desc_help, etc.)
  that users can customize per locale. setMyCommands registers all
  locales explicitly.

- Removed locale from CommandConfig: no longer needed since locale
  is derived from the Telegram user's language at runtime.

- Debounced command auto-sync: after command config/tracker changes,
  affected bots are marked dirty and synced after a 30s debounce
  window. Manual "Sync with Telegram" button still works.

- Entity pickers in LinkedTargetsSection: replaced 6 plain <select>
  elements with EntitySelect components (search, icons, keyboard nav).
  Added onselect callback and size="sm" props to EntitySelect.

frontend/src/routes/notification-trackers/LinkedTargetsSection.svelte

@@ -3,6 +3,8 @@
 	import { t } from '$lib/i18n';
 	import MdiIcon from '$lib/components/MdiIcon.svelte';
 	import IconButton from '$lib/components/IconButton.svelte';
+	import EntitySelect from '$lib/components/EntitySelect.svelte';
+	import type { EntityItem } from '$lib/components/EntitySelect.svelte';
 	import type { Tracker, NotificationTarget, TrackingConfig, TemplateConfig } from '$lib/types';
 
 	interface Props {
@@ -44,6 +46,23 @@
 		onchangeNewTrackingConfig,
 		onchangeNewTemplateConfig,
 	}: Props = $props();
+
+	function toItems(configs: any[]): EntityItem[] {
+		return configsForTracker(configs).map(c => ({
+			value: c.id,
+			label: c.name,
+			icon: c.icon || '',
+		}));
+	}
+
+	const trackingConfigItems = $derived(toItems(trackingConfigs));
+	const templateConfigItems = $derived(toItems(templateConfigs));
+	const targetItems = $derived<EntityItem[]>(unlinkedTargets.map(tgt => ({
+		value: tgt.id,
+		label: tgt.name,
+		icon: tgt.icon || (tgt.type === 'telegram' ? 'mdiSend' : 'mdiWebhook'),
+		desc: tgt.type,
+	})));
 </script>
 
 <div class="mt-3 border-t border-[var(--color-border)] pt-3 space-y-2" in:slide>
@@ -61,18 +80,16 @@
 					{/if}
 				</div>
 				<div class="flex items-center gap-2 flex-wrap justify-end">
-					<select value={tt.tracking_config_id || 0}
-						onchange={(e: Event) => onupdateLink(tt, 'tracking_config_id', Number((e.target as HTMLSelectElement).value) || null)}
-						class="text-xs px-2 py-1 border border-[var(--color-border)] rounded-md bg-[var(--color-background)]">
-						<option value={0}>— {t('trackingConfig.title')} —</option>
-						{#each configsForTracker(trackingConfigs) as tc}<option value={tc.id}>{tc.name}</option>{/each}
-					</select>
-					<select value={tt.template_config_id || 0}
-						onchange={(e: Event) => onupdateLink(tt, 'template_config_id', Number((e.target as HTMLSelectElement).value) || null)}
-						class="text-xs px-2 py-1 border border-[var(--color-border)] rounded-md bg-[var(--color-background)]">
-						<option value={0}>— {t('templateConfig.title')} —</option>
-						{#each configsForTracker(templateConfigs) as tc}<option value={tc.id}>{tc.name}</option>{/each}
-					</select>
+					<div class="min-w-[140px]">
+						<EntitySelect items={trackingConfigItems} value={tt.tracking_config_id}
+							placeholder={'— ' + t('trackingConfig.title') + ' —'} size="sm" allowNone noneLabel={'— ' + t('trackingConfig.title') + ' —'}
+							onselect={(v) => onupdateLink(tt, 'tracking_config_id', Number(v) || null)} />
+					</div>
+					<div class="min-w-[140px]">
+						<EntitySelect items={templateConfigItems} value={tt.template_config_id}
+							placeholder={'— ' + t('templateConfig.title') + ' —'} size="sm" allowNone noneLabel={'— ' + t('templateConfig.title') + ' —'}
+							onselect={(v) => onupdateLink(tt, 'template_config_id', Number(v) || null)} />
+					</div>
 					<div class="relative">
 						<IconButton icon="mdiDotsVertical" size={14} title={t('common.test')}
 							onclick={(e: MouseEvent) => onopenTestMenu(tt.id, e)}
@@ -91,24 +108,21 @@
 	<!-- Add target link -->
 	{#if unlinkedTargets.length > 0}
 		<div class="flex items-center gap-2 mt-2">
-			<select value={newLinkTargetId}
-				onchange={(e: Event) => onchangeNewTarget(Number((e.target as HTMLSelectElement).value))}
-				class="text-xs px-2 py-1 border border-[var(--color-border)] rounded-md bg-[var(--color-background)] flex-1">
-				<option value={0}>— {t('notificationTracker.addTarget')} —</option>
-				{#each unlinkedTargets as tgt}<option value={tgt.id}>{tgt.name} ({tgt.type})</option>{/each}
-			</select>
-			<select value={newLinkTrackingConfigId}
-				onchange={(e: Event) => onchangeNewTrackingConfig(Number((e.target as HTMLSelectElement).value))}
-				class="text-xs px-2 py-1 border border-[var(--color-border)] rounded-md bg-[var(--color-background)]">
-				<option value={0}>— {t('trackingConfig.title')} —</option>
-				{#each configsForTracker(trackingConfigs) as tc}<option value={tc.id}>{tc.name}</option>{/each}
-			</select>
-			<select value={newLinkTemplateConfigId}
-				onchange={(e: Event) => onchangeNewTemplateConfig(Number((e.target as HTMLSelectElement).value))}
-				class="text-xs px-2 py-1 border border-[var(--color-border)] rounded-md bg-[var(--color-background)]">
-				<option value={0}>— {t('templateConfig.title')} —</option>
-				{#each configsForTracker(templateConfigs) as tc}<option value={tc.id}>{tc.name}</option>{/each}
-			</select>
+			<div class="flex-1 min-w-[140px]">
+				<EntitySelect items={targetItems} value={newLinkTargetId || null}
+					placeholder={'— ' + t('notificationTracker.addTarget') + ' —'} size="sm"
+					onselect={(v) => onchangeNewTarget(Number(v) || 0)} />
+			</div>
+			<div class="min-w-[140px]">
+				<EntitySelect items={trackingConfigItems} value={newLinkTrackingConfigId || null}
+					placeholder={'— ' + t('trackingConfig.title') + ' —'} size="sm" allowNone noneLabel={'— ' + t('trackingConfig.title') + ' —'}
+					onselect={(v) => onchangeNewTrackingConfig(Number(v) || 0)} />
+			</div>
+			<div class="min-w-[140px]">
+				<EntitySelect items={templateConfigItems} value={newLinkTemplateConfigId || null}
+					placeholder={'— ' + t('templateConfig.title') + ' —'} size="sm" allowNone noneLabel={'— ' + t('templateConfig.title') + ' —'}
+					onselect={(v) => onchangeNewTemplateConfig(Number(v) || 0)} />
+			</div>
 			<button onclick={onaddLink}
 				disabled={!newLinkTargetId || addingTarget}
 				class="text-xs px-3 py-1 bg-[var(--color-primary)] text-[var(--color-primary-foreground)] rounded hover:opacity-90 disabled:opacity-50">