fix: the Latest feed's filter dropdowns opened empty

Operator: "the filters in the latest feed, drop down but don't have values". Two separate causes:

- Platform: PostsFilterBar built its items from `platformsStore.platforms`. The platforms store has never had that property; it exposes `list` and `byKey`. The read returned undefined, `|| []` turned that into an empty list, and nothing failed. ArtistsView had copied the same read, so the Browse → Artists platform filter was empty too. Both now read `list` and show platform names rather than raw keys.

- Artist: the autocomplete searched the server only after something was typed (autocomplete returns [] for an empty query by design, which its tests pin). Opening the dropdown therefore showed an empty menu. PostsFilterBar now loads every artist once from a new lightweight `GET /api/artists/names` (id, name, slug; alphabetical; no joins) and filters client-side, so the list is there on open. A deep-linked artist_id now also shows the artist's real name instead of "Artist #id".

Guard: frontend/test/storeUsage.spec.js scans src for `platformsStore.<name>` and fails on any name the store doesn't define, since the frontend CI has no type-checker to catch this. A positive control shows the shipped `platformsStore.platforms` read is flagged, and a vacuity check confirms the scan really walks the tree.

tests/test_api_artists_create.py covers /names.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SHQB1YukL3VyvMK8rcbmV9

frontend/src/components/posts/PostsFilterBar.vue

@@ -1,21 +1,22 @@
 <template>
   <div class="fc-posts-filters">
+    <!-- The full artist list, filtered client-side as you type. This used to
+         search the server only once something was typed, so opening the
+         dropdown showed an empty menu. -->
     <v-autocomplete
       v-model="artistModel"
       :items="artistOptions"
       :loading="artistLoading"
-      :search="artistQuery"
       item-title="name"
       item-value="id"
       label="Artist"
       density="compact"
       hide-details
       clearable
-      no-filter
       return-object
+      no-data-text="No matching artists"
       class="fc-posts-filters__artist"
-      @update:search="onArtistSearch"
-      @update:model-value="onArtistPicked"
+      @update:model-value="emitFilters"
     />
 
     <v-select
@@ -39,7 +40,8 @@
 
 <script setup>
 import { computed, onMounted, ref, watch } from 'vue'
-import { useSourcesStore } from '../../stores/sources.js'
+
+import { useApi } from '../../composables/useApi.js'
 import { usePlatformsStore } from '../../stores/platforms.js'
 
 const props = defineProps({
@@ -48,18 +50,19 @@ const props = defineProps({
 })
 const emit = defineEmits(['update:filters'])
 
-const sourcesStore = useSourcesStore()
+const api = useApi()
 const platformsStore = usePlatformsStore()
 
-// Artist autocomplete state
-const artistQuery = ref('')
 const artistOptions = ref([])
 const artistLoading = ref(false)
 const artistModel = ref(null)
 
-// Platform v-select state
+// `list`, not `platforms`: the store has never had a `platforms` property, so
+// this read undefined and the dropdown opened empty.
+// test/storeUsage.spec.js now fails on any read of a property the store does
+// not define.
 const platformItems = computed(() =>
-  (platformsStore.platforms || []).map(p => ({ title: p.key, value: p.key }))
+  platformsStore.list.map(p => ({ title: p.name || p.key, value: p.key }))
 )
 const platformModel = ref(props.platform)
 
@@ -67,29 +70,6 @@ const hasFilters = computed(
   () => artistModel.value != null || platformModel.value != null
 )
 
-let _searchTimer = null
-function onArtistSearch(q) {
-  artistQuery.value = q
-  clearTimeout(_searchTimer)
-  if (!q || !q.trim()) {
-    artistOptions.value = artistModel.value ? [artistModel.value] : []
-    return
-  }
-  _searchTimer = setTimeout(async () => {
-    artistLoading.value = true
-    try {
-      const results = await sourcesStore.autocompleteArtist(q, 20)
-      artistOptions.value = results
-    } finally {
-      artistLoading.value = false
-    }
-  }, 200)
-}
-
-function onArtistPicked() {
-  emitFilters()
-}
-
 function emitFilters() {
   emit('update:filters', {
     artist_id: artistModel.value?.id ?? null,
@@ -100,30 +80,38 @@ function emitFilters() {
 function clearAll() {
   artistModel.value = null
   platformModel.value = null
-  artistOptions.value = []
-  artistQuery.value = ''
   emitFilters()
 }
 
-onMounted(async () => {
-  await platformsStore.loadAll()
-  // If a deep-link arrives with an artist_id, hydrate the selected display.
-  if (props.artistId != null) {
-    const seed = { id: props.artistId, name: `Artist #${props.artistId}` }
-    artistModel.value = seed
-    artistOptions.value = [seed]
+// A deep link carries only the id. Once the list is loaded, show the real name
+// rather than a placeholder.
+function selectArtistById(id) {
+  if (id == null) {
+    artistModel.value = null
+    return
   }
+  if (artistModel.value?.id === id) return
+  artistModel.value = artistOptions.value.find(a => a.id === id)
+    || { id, name: `Artist #${id}` }
+}
+
+async function loadArtists() {
+  artistLoading.value = true
+  try {
+    artistOptions.value = await api.get('/api/artists/names')
+  } catch {
+    artistOptions.value = []
+  } finally {
+    artistLoading.value = false
+  }
+}
+
+onMounted(async () => {
+  await Promise.all([platformsStore.loadAll(), loadArtists()])
+  selectArtistById(props.artistId)
 })
 
-watch(() => props.artistId, (val) => {
-  if (val == null) {
-    artistModel.value = null
-  } else if (artistModel.value?.id !== val) {
-    const seed = { id: val, name: `Artist #${val}` }
-    artistModel.value = seed
-    artistOptions.value = [seed]
-  }
-})
+watch(() => props.artistId, (val) => selectArtistById(val))
 
 watch(() => props.platform, (val) => {
   if (platformModel.value !== val) platformModel.value = val || null

frontend/src/views/ArtistsView.vue

@@ -58,8 +58,9 @@ useInfiniteScroll(sentinelEl, () => {
 
 onMounted(async () => {
   await platformsStore.loadAll()
-  platformItems.value = (platformsStore.platforms || []).map(p => ({
-    title: p.key, value: p.key,
+  // `list` — the store has no `platforms` property (test/storeUsage.spec.js).
+  platformItems.value = platformsStore.list.map(p => ({
+    title: p.name || p.key, value: p.key,
   }))
   // Apply any deep-linked q (and load). setQuery resets + fetches.
   store.setQuery(searchTerm.value || '')