refactor: remove standalone proxies, add Traefik provider with Docker labels

Standalone proxy removal:
- Delete store, API handlers, proxy manager, health monitor, validator, hints
- Delete frontend pages (proxies list, create, edit) and components (ProxyCard, ProxyForm, ProxyFilter, ProxyGroup, ValidationChecklist)
- Remove proxy routes from router, nav items, dashboard references
- Clean up SystemHealthCard to remove proxy section

Traefik provider:
- Add TraefikProvider implementing proxy.Provider via Docker labels
- ContainerLabels() returns traefik.enable, router rule, entrypoints, service port, TLS cert resolver, docker network
- ConfigureRoute() returns router name (labels handle routing at container creation)
- DeleteRoute() is no-op (container removal auto-deregisters)
- Ping() checks Traefik API health (optional)
- Wire ContainerLabels into deployer (executeDeploy + blueGreenDeploy)
- Add Traefik settings: entrypoint, cert_resolver, network, api_url
- Add traefik option to proxy provider selector in settings UI
- Show conditional Traefik config fields
- Add i18n keys (EN + RU)

web/src/routes/settings/+page.svelte

@@ -26,6 +26,12 @@
 	// Proxy provider state.
 	let proxyProvider = $state('npm');
 
+	// Traefik settings state.
+	let traefikEntrypoint = $state('websecure');
+	let traefikCertResolver = $state('letsencrypt');
+	let traefikNetwork = $state('');
+	let traefikApiUrl = $state('');
+
 	// DNS settings state.
 	let wildcardDns = $state(true);
 	let dnsProvider = $state('');
@@ -91,6 +97,10 @@
 			notificationUrl = settings.notification_url ?? '';
 			staleThresholdDays = String(settings.stale_threshold_days ?? 7);
 			proxyProvider = settings.proxy_provider ?? 'npm';
+			traefikEntrypoint = settings.traefik_entrypoint ?? 'websecure';
+			traefikCertResolver = settings.traefik_cert_resolver ?? 'letsencrypt';
+			traefikNetwork = settings.traefik_network ?? '';
+			traefikApiUrl = settings.traefik_api_url ?? '';
 			wildcardDns = settings.wildcard_dns ?? true;
 			dnsProvider = settings.dns_provider ?? '';
 			hasCloudflareApiToken = settings.has_cloudflare_api_token ?? false;
@@ -118,6 +128,10 @@
 				subdomain_pattern: subdomainPattern.trim(), polling_interval: pollingInterval.trim(),
 				base_volume_path: baseVolumePath.trim(), notification_url: notificationUrl.trim(),
 				proxy_provider: proxyProvider,
+				traefik_entrypoint: traefikEntrypoint.trim() || 'websecure',
+				traefik_cert_resolver: traefikCertResolver.trim(),
+				traefik_network: traefikNetwork.trim(),
+				traefik_api_url: traefikApiUrl.trim(),
 				stale_threshold_days: Math.max(1, parseInt(staleThresholdDays, 10) || 7),
 				wildcard_dns: wildcardDns,
 				dns_provider: wildcardDns ? '' : dnsProvider,
@@ -290,12 +304,27 @@
 							<p class="text-xs text-[var(--text-tertiary)]">{$t('settings.proxyNpmDesc')}</p>
 						</div>
 					</label>
+					<label class="flex flex-1 cursor-pointer items-start gap-3 rounded-lg border p-3 transition-colors {proxyProvider === 'traefik' ? 'border-[var(--color-brand-500)] bg-[var(--surface-card-hover)]' : 'border-[var(--border-primary)] hover:bg-[var(--surface-card-hover)]'}">
+						<input type="radio" bind:group={proxyProvider} value="traefik" class="mt-0.5 h-4 w-4 text-[var(--color-brand-600)] focus:ring-[var(--color-brand-500)]" />
+						<div>
+							<span class="text-sm font-medium text-[var(--text-primary)]">{$t('settings.proxyTraefik')}</span>
+							<p class="text-xs text-[var(--text-tertiary)]">{$t('settings.proxyTraefikDesc')}</p>
+						</div>
+					</label>
 				</div>
 				{#if proxyProvider === 'none'}
 					<div class="mt-3 rounded-lg border border-amber-300 bg-amber-50 dark:border-amber-700 dark:bg-amber-950/30 p-3">
 						<p class="text-sm text-amber-800 dark:text-amber-300">{$t('settings.proxyNoneWarning')}</p>
 					</div>
 				{/if}
+				{#if proxyProvider === 'traefik'}
+					<div class="mt-3 grid grid-cols-1 gap-3 sm:grid-cols-2 rounded-lg border border-[var(--border-primary)] bg-[var(--surface-card-hover)] p-4">
+						<FormField label={$t('settings.traefikEntrypoint')} name="traefikEntrypoint" bind:value={traefikEntrypoint} placeholder="websecure" helpText={$t('settings.traefikEntrypointHelp')} />
+						<FormField label={$t('settings.traefikCertResolver')} name="traefikCertResolver" bind:value={traefikCertResolver} placeholder="letsencrypt" helpText={$t('settings.traefikCertResolverHelp')} />
+						<FormField label={$t('settings.traefikNetwork')} name="traefikNetwork" bind:value={traefikNetwork} placeholder="" helpText={$t('settings.traefikNetworkHelp')} />
+						<FormField label={$t('settings.traefikApiUrl')} name="traefikApiUrl" bind:value={traefikApiUrl} placeholder="http://traefik:8080" helpText={$t('settings.traefikApiUrlHelp')} />
+					</div>
+				{/if}
 			</div>
 
 			<!-- SSL Certificate moved to Credentials page -->