fix(artists): card preview dead-space + empty-state flicker on first load

Two operator-reported Artists-view bugs.

Layout: ArtistCard previews used aspect-ratio: 3/1 + max-height: 220px — when a
lone grid column got wide (>~660px), the max-height made the aspect-ratio box
shrink its own WIDTH to keep the ratio, leaving dead space beside the 3
thumbnails. Dropped max-height (kept the min-height floor) so the strip fills the
card width; lowered the grid min 440→360px so a lone column stays <732px (strip
≲244px) and desktop gets 2+ columns.

Flicker: isEmpty checked !loading, but on the first render loading is still false
(the initial loadMore fires in onMounted, after paint) so "No artists match"
flashed for a frame before the spinner/data. Added a reactive `loaded` flag (true
after the first load attempt, reset on reset()); isEmpty now also requires it.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/src/components/discovery/ArtistCard.vue

@@ -49,9 +49,11 @@ function onCardClick() {
   position: relative;
   display: grid; grid-template-columns: repeat(3, 1fr);
   gap: 2px; aspect-ratio: 3 / 1;
-  /* Explicit floor + ceiling so tall source images can't escape the
-     preview slot even on browsers where aspect-ratio doesn't compute. */
-  min-height: 150px; max-height: 220px;
+  /* Floor so tall source images can't escape the slot. NO max-height: an
+     aspect-ratio box capped by max-height shrinks its own WIDTH to keep the
+     ratio, leaving dead space beside the previews on a wide (single-column)
+     card. The grid below keeps columns ≲400px so the strip stays a sane height. */
+  min-height: 120px;
   overflow: hidden;
   background: rgb(var(--v-theme-surface-light));
 }

frontend/src/stores/artistDirectory.js

@@ -14,6 +14,10 @@ export const useArtistDirectoryStore = defineStore('artistDirectory', () => {
   const q = ref('')
   const platform = ref(null)
   let started = false
+  // Has a load ATTEMPT completed yet? Gates the "No artists match" empty state
+  // so it can't flash on the very first render (loading is still false before
+  // onMounted fires the first loadMore) or between a query change and its fetch.
+  const loaded = ref(false)
   // Typed "alice" then "alice bob" used to drop the second fetch
   // entirely (loading flag still true from the first), so the UI
   // showed alice results while the input said "alice bob". Inflight
@@ -35,6 +39,7 @@ export const useArtistDirectoryStore = defineStore('artistDirectory', () => {
       nextCursor.value = body.next_cursor
       started = true
     })
+    if (t.isCurrent()) loaded.value = true
   }
 
   async function reset() {
@@ -42,6 +47,7 @@ export const useArtistDirectoryStore = defineStore('artistDirectory', () => {
     cards.value = []
     nextCursor.value = null
     started = false
+    loaded.value = false
     await loadMore()
   }
 
@@ -50,7 +56,8 @@ export const useArtistDirectoryStore = defineStore('artistDirectory', () => {
 
   const hasMore = computed(() => !started || nextCursor.value !== null)
   const isEmpty = computed(
-    () => !loading.value && cards.value.length === 0 && error.value === null
+    () => loaded.value && !loading.value
+      && cards.value.length === 0 && error.value === null
   )
 
   return {

frontend/src/views/ArtistsView.vue

@@ -76,9 +76,11 @@ onMounted(async () => {
 }
 .fc-artists__grid {
   display: grid;
-  /* min(440px, 100%) so a card never exceeds the viewport — on phones the
-     min-track collapses to 100% (single column) instead of overflowing. */
-  grid-template-columns: repeat(auto-fill, minmax(min(440px, 100%), 1fr));
+  /* min(360px, 100%) so a card never exceeds the viewport (phones collapse to
+     one column). 360 keeps a LONE column under ~732px wide, so the 3/1 preview
+     strip stays ≲244px tall and always fills the card width (no dead space),
+     while giving 2+ columns on a normal desktop. */
+  grid-template-columns: repeat(auto-fill, minmax(min(360px, 100%), 1fr));
   gap: 12px;
 }
 .fc-artists__sentinel {