fix(dashboard): add missing getPlatformColor helper for platform health bars

The platform-health row icon binds to getPlatformColor(row.platform) but the
helper was only present in Sources.vue/Subscriptions.vue/Credentials.vue/
Settings.vue — not copied into Dashboard.vue when the template was introduced,
so the icons next to each platform row rendered in Vuetify's default color.
Also collapse the double blank line left where sourcesWithErrors was removed.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/src/views/Dashboard.vue

@@ -383,7 +383,6 @@ const failingSources = computed(() => {
 
 const totalFailingCount = computed(() => failingSources.value.length)
 
-
 const failedCount = computed(() => stats.value?.active_failed || 0)
 const activeDownloadsCount = computed(() =>
   (stats.value?.queued || 0) + (stats.value?.running || 0)
@@ -573,6 +572,18 @@ function getPlatformIcon(platform) {
   return icons[platform] || 'mdi-web'
 }
 
+function getPlatformColor(platform) {
+  const colors = {
+    patreon: 'red',
+    subscribestar: 'amber',
+    hentaifoundry: 'purple',
+    discord: 'indigo',
+    pixiv: 'blue',
+    deviantart: 'green',
+  }
+  return colors[platform] || 'grey'
+}
+
 function getStatusColor(status) {
   const colors = {
     completed: 'success',