fix: UI polish — overflow, placeholders, dashboard provider card

- Fix bot card header overflow by replacing "Sync with Telegram" text
  button with icon button, add flex-wrap
- Rename sync button label to "Sync Commands"
- Remove decorative dashes from selector placeholders (— X — → X)
- Show selected provider name/icon in dashboard stat card when global
  provider filter is active
- Add selector placeholder convention to frontend-architecture.md

frontend/src/routes/+page.svelte

@@ -177,8 +177,12 @@
 
 	let displayCommandTrackers = $state(0);
 
+	const filteredProvider = $derived(globalProviderFilter.id ? providers.find(p => p.id === globalProviderFilter.id) : null);
+
 	const statCards = $derived(status ? [
-		{ icon: 'mdiServer', label: 'dashboard.providers', value: displayProviders, color: '#0d9488' },
+		filteredProvider
+			? { icon: providerDefaultIcon(filteredProvider), label: filteredProvider.name, value: filteredProvider.type, color: '#0d9488', isProvider: true }
+			: { icon: 'mdiServer', label: 'dashboard.providers', value: displayProviders, color: '#0d9488' },
 		{ icon: 'mdiRadar', label: 'dashboard.activeTrackers', value: displayActive, suffix: ` / ${displayTotal}`, color: '#6366f1' },
 		{ icon: 'mdiTarget', label: 'dashboard.targets', value: displayTargets, color: '#f59e0b' },
 		...(status.command_trackers !== undefined ? [{ icon: 'mdiConsoleLine', label: 'nav.commandTrackers', value: displayCommandTrackers, color: '#8b5cf6' }] : []),
@@ -234,10 +238,14 @@
 							<MdiIcon name={card.icon} size={22} />
 						</div>
 						<div>
-							<p class="text-sm" style="color: var(--color-muted-foreground);">{t(card.label)}</p>
-							<p class="stat-value font-mono" style="animation-delay: {i * 80 + 200}ms;">
-								{card.value}{#if card.suffix}<span class="stat-suffix">{card.suffix}</span>{/if}
-							</p>
+							<p class="text-sm" style="color: var(--color-muted-foreground);">{card.isProvider ? card.label : t(card.label)}</p>
+							{#if card.isProvider}
+								<p class="text-lg font-medium" style="color: {card.color};">{card.value}</p>
+							{:else}
+								<p class="stat-value font-mono" style="animation-delay: {i * 80 + 200}ms;">
+									{card.value}{#if card.suffix}<span class="stat-suffix">{card.suffix}</span>{/if}
+								</p>
+							{/if}
 						</div>
 					</div>
 				</div>