feat: locale-aware notification templates + UX improvements

- Add locale support to notification templates (matching command template
  pattern): TemplateSlot now has locale field with (config_id, slot_name,
  locale) uniqueness, nested API format {slot: {locale: template}}
- Migration merges separate EN/RU system configs into unified per-provider
  configs; seeds create one config per provider with multi-locale slots
- Locale-aware dispatch with EN fallback in NotificationDispatcher
- Frontend locale tabs (EN/RU) on template config editor
- Fix tracking config cards not showing default provider icons
- Global provider filter, search palette, and various UX polish

frontend/src/routes/bots/TelegramBotTab.svelte

@@ -10,6 +10,7 @@
 	import EmptyState from '$lib/components/EmptyState.svelte';
 	import ConfirmModal from '$lib/components/ConfirmModal.svelte';
 	import IconButton from '$lib/components/IconButton.svelte';
+	import EntitySelect from '$lib/components/EntitySelect.svelte';
 	import { snackSuccess, snackError, snackInfo } from '$lib/stores/snackbar.svelte';
 	import type { TelegramBot, TelegramChat } from '$lib/types';
 
@@ -104,6 +105,40 @@
 		} catch (err: any) { snackError(err.message); }
 	}
 
+	const LANG_ITEMS = [
+		{ value: '', label: '—', icon: 'mdiTranslate', desc: 'Auto' },
+		{ value: 'en', label: 'EN', icon: 'mdiAlphaECircle', desc: 'English' },
+		{ value: 'ru', label: 'RU', icon: 'mdiAlphaRCircle', desc: 'Русский' },
+		{ value: 'uk', label: 'UK', icon: 'mdiAlphaUCircle', desc: 'Українська' },
+		{ value: 'de', label: 'DE', icon: 'mdiAlphaDCircle', desc: 'Deutsch' },
+		{ value: 'fr', label: 'FR', icon: 'mdiAlphaFCircle', desc: 'Français' },
+		{ value: 'es', label: 'ES', icon: 'mdiAlphaECircle', desc: 'Español' },
+		{ value: 'it', label: 'IT', icon: 'mdiAlphaICircle', desc: 'Italiano' },
+		{ value: 'pt', label: 'PT', icon: 'mdiAlphaPCircle', desc: 'Português' },
+		{ value: 'zh', label: 'ZH', icon: 'mdiAlphaZCircle', desc: '中文' },
+		{ value: 'ja', label: 'JA', icon: 'mdiAlphaJCircle', desc: '日本語' },
+		{ value: 'ko', label: 'KO', icon: 'mdiAlphaKCircle', desc: '한국어' },
+		{ value: 'pl', label: 'PL', icon: 'mdiAlphaPCircle', desc: 'Polski' },
+		{ value: 'nl', label: 'NL', icon: 'mdiAlphaNCircle', desc: 'Nederlands' },
+		{ value: 'tr', label: 'TR', icon: 'mdiAlphaTCircle', desc: 'Türkçe' },
+		{ value: 'ar', label: 'AR', icon: 'mdiAlphaACircle', desc: 'العربية' },
+		{ value: 'hi', label: 'HI', icon: 'mdiAlphaHCircle', desc: 'हिन्दी' },
+	];
+
+	async function updateChatLanguage(botId: number, chat: TelegramChat, lang: string) {
+		try {
+			await api(`/telegram-bots/${botId}/chats/${chat.id}`, {
+				method: 'PUT',
+				body: JSON.stringify({ language_code: lang }),
+			});
+			// Update local state immutably
+			chats[botId] = (chats[botId] || []).map(c =>
+				c.id === chat.id ? { ...c, language_code: lang } : c
+			);
+			snackSuccess(t('telegramBot.languageUpdated'));
+		} catch (err: any) { snackError(err.message); }
+	}
+
 	async function loadListenerStatus(botId: number) {
 		botListenerLoading = { ...botListenerLoading, [botId]: true };
 		try {
@@ -302,28 +337,43 @@
 						{:else if (chats[bot.id] || []).length === 0}
 							<p class="text-xs text-[var(--color-muted-foreground)]">{t('telegramBot.noChats')}</p>
 						{:else}
-							<div class="space-y-1">
-								{#each chats[bot.id] as chat}
-									<div class="flex items-center justify-between text-sm px-2 py-1 rounded hover:bg-[var(--color-muted)] cursor-pointer"
-										onclick={(e: MouseEvent) => copyChatId(e, chat.chat_id)}
-										title={t('telegramBot.clickToCopy')}
-										role="button" tabindex="0">
-										<div class="flex items-center gap-2">
-											<span class="font-medium">{chat.title || chat.username || 'Unknown'}</span>
-											<span class="text-xs px-1.5 py-0.5 rounded bg-[var(--color-muted)] text-[var(--color-muted-foreground)]">{chatTypeLabel(chat.type)}</span>
-											{#if chat.language_code}<span class="text-xs px-1.5 py-0.5 rounded bg-[var(--color-muted)] text-[var(--color-muted-foreground)]">{chat.language_code.toUpperCase()}</span>{/if}
-											<span class="text-xs text-[var(--color-muted-foreground)] font-mono">{chat.chat_id}</span>
-										</div>
-										<div class="flex items-center gap-1">
+							{@const gridStyle = "display:grid; grid-template-columns:1fr 80px 100px 130px 60px; align-items:center; gap:0.5rem;"}
+							<!-- Header -->
+							<div style="{gridStyle} padding:0.25rem 0.5rem; border-bottom:1px solid var(--color-border);"
+								class="text-[0.65rem] font-semibold uppercase tracking-wide text-[var(--color-muted-foreground)]">
+								<span>{t('telegramBot.chatName')}</span>
+								<span style="text-align:center">{t('telegramBot.chatType')}</span>
+								<span style="text-align:center">{t('telegramBot.chatLang')}</span>
+								<span style="text-align:center">{t('telegramBot.chatId')}</span>
+								<span></span>
+							</div>
+							<!-- Rows -->
+							{#each chats[bot.id] as chat}
+								<div style={gridStyle}
+									class="text-sm px-2 py-1.5 rounded hover:bg-[var(--color-muted)] cursor-pointer"
+									onclick={(e: MouseEvent) => copyChatId(e, chat.chat_id)}
+									title={t('telegramBot.clickToCopy')}
+									role="button" tabindex="0">
+									<span class="font-medium truncate">{chat.title || chat.username || 'Unknown'}</span>
+									<span style="text-align:center" class="text-xs px-1.5 py-0.5 rounded bg-[var(--color-muted)] text-[var(--color-muted-foreground)]">{chatTypeLabel(chat.type)}</span>
+									<div style="justify-self:center" onclick={(e: MouseEvent) => e.stopPropagation()}>
+										<EntitySelect
+											items={LANG_ITEMS}
+											value={chat.language_code || ''}
+											size="sm"
+											onselect={(val) => updateChatLanguage(bot.id, chat, String(val ?? ''))}
+										/>
+									</div>
+									<span style="text-align:center" class="text-xs text-[var(--color-muted-foreground)] font-mono">{chat.chat_id}</span>
+									<div style="justify-self:end" class="flex items-center gap-1">
 										<IconButton icon="mdiSend" title="Test message" size={14}
 											onclick={(e: MouseEvent) => testChat(e, bot.id, chat.chat_id)}
 											disabled={chatTesting[`${bot.id}_${chat.chat_id}`]} />
 										<IconButton icon="mdiDelete" title={t('common.delete')} size={14}
 											onclick={(e: MouseEvent) => { e.stopPropagation(); deleteChat(bot.id, chat.id); }} variant="danger" />
 									</div>
-									</div>
-								{/each}
-							</div>
+								</div>
+							{/each}
 						{/if}
 						<button onclick={() => discoverChats(bot.id)}
 							class="text-xs text-[var(--color-primary)] hover:underline mt-2 flex items-center gap-1">
@@ -435,3 +485,4 @@
 
 <ConfirmModal open={confirmDelete !== null} message={t('telegramBot.confirmDelete')}
 	onconfirm={() => confirmDelete?.onconfirm()} oncancel={() => confirmDelete = null} />
+