feat(posts): plain bold titles; reserve View-original to the post card; provenance links to the posts feed

- Post titles arrived as stored HTML (e.g. <strong>…</strong>) rendering as
  literal markup. New toPlainText() strips tags; titles render plain + bold
  (ProvenancePanel and PostCard).
- Removed "View original post" from the provenance panel (modal) — the
  open-original button lives on the PostCard (the post view).
- Provenance "View post" now navigates to the /posts feed (post_id query),
  not the gallery image grid. (Feed in-context landing lands next.)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/components/modal/ProvenancePanel.vue

@@ -19,7 +19,7 @@
           <span v-if="postDate(e)" class="fc-prov__date">{{ postDate(e) }}</span>
         </div>
         <div class="fc-prov__post">
-          {{ e.post.title || `Post ${e.post.external_post_id}` }}
+          {{ postTitle(e) }}
         </div>
         <div class="fc-prov__meta">
           <RouterLink :to="`/artist/${e.artist.slug}`">
@@ -30,12 +30,8 @@
           </span>
         </div>
         <div class="fc-prov__actions">
-          <a
-            v-if="e.post.url" :href="e.post.url"
-            target="_blank" rel="noopener noreferrer"
-          >↗ View original post</a>
           <a href="#" @click.prevent="openPost(e.post.id)">
-            View images from this post
+            View post
           </a>
           <a
             v-if="e.post.description_html"
@@ -83,6 +79,7 @@ import { useRouter } from 'vue-router'
 import { useModalStore } from '../../stores/modal.js'
 import { useProvenanceStore } from '../../stores/provenance.js'
 import { formatPostDate } from '../../utils/date.js'
+import { toPlainText } from '../../utils/htmlSanitize.js'
 
 const modal = useModalStore()
 const prov = useProvenanceStore()
@@ -134,9 +131,16 @@ const show = computed(() => {
 const attachments = computed(() => state.value?.attachments || [])
 
 function postDate(e) { return formatPostDate(e.post.date) }
+function postTitle(e) {
+  // Titles can arrive as stored HTML (e.g. "<strong>…</strong>"); render
+  // as plain text (the CSS makes it bold).
+  return toPlainText(e.post.title) || `Post ${e.post.external_post_id}`
+}
 
 function openPost(postId) {
-  router.push({ path: '/gallery', query: { post_id: postId } })
+  // Land on the post in the posts feed (in context), not the gallery
+  // image grid. Operator-flagged 2026-05-28.
+  router.push({ path: '/posts', query: { post_id: postId } })
   modal.close()
 }
 </script>
@@ -159,7 +163,7 @@ function openPost(postId) {
   text-transform: lowercase;
 }
 .fc-prov__post {
-  font-weight: 600; margin: 4px 0;
+  font-weight: 700; margin: 4px 0;
   color: rgb(var(--v-theme-on-surface));
 }
 .fc-prov__meta {