fix(modal): Esc closes from tag input; Provenance cards scroll at ~2.5

Two operator-flagged UX gaps from 2026-06-01:

1. **Esc trapped inside the tag-entry field**
   The autofocused TagAutocomplete input made Esc-to-close unreachable
   because ImageViewer's keydown handler bailed early on
   `isTextEntry(ev.target)` for every key including Escape. Now Escape
   closes the modal from text inputs too — except when a Vuetify
   overlay is open (FandomPicker, autocomplete dropdown, suggestion
   3-dot menu), in which case that overlay's own Esc-handling fires
   instead of closing the whole modal mid-interaction. Detected via
   `.v-overlay--active`. Arrow keys still gate on isTextEntry so the
   tag input handles typing without navigating images.

2. **Provenance cards expanded the side panel unbounded**
   When an image had many ImageProvenance entries the cards stack
   pushed the Tags section below the fold. Wrapped the cards in a
   `.fc-prov__cards` container with max-height 270px (≈2.5 cards) and
   thin overflow scrollbar. Title stays anchored at top; Tags panel
   sits at a consistent position below regardless of provenance count.

frontend/src/components/modal/ProvenancePanel.vue

@@ -10,7 +10,11 @@
       density="compact"
     >{{ state.error }}</v-alert>
 
-    <template v-else>
+    <!-- Cards scroll independently of the section title + attachments
+         below them. Cap at ~2.5 cards visible (operator-asked 2026-06-01:
+         keeps the Tags section anchored below at a consistent position;
+         the half-visible third card hints there's more). -->
+    <div v-else class="fc-prov__cards">
       <article
         v-for="e in state.entries" :key="e.provenance_id" class="fc-prov__card"
       >
@@ -58,7 +62,7 @@
           </RouterLink>
         </div>
       </article>
-    </template>
+    </div>
 
     <div v-if="attachments.length" class="fc-prov__attach">
       <h4 class="fc-prov__attach-title">Attachments</h4>
@@ -159,6 +163,18 @@ function openPost(postId, artistId) {
   color: rgb(var(--v-theme-on-surface));
   margin-bottom: 12px;
 }
+.fc-prov__cards {
+  /* 2.5 cards-worth at the typical collapsed card height (~108px each
+     incl. 10px gap). Slightly under to ensure the third card's bottom
+     edge is clipped — the visual cue that there's more below. */
+  max-height: 270px;
+  overflow-y: auto;
+  /* Hairline scrollbar that doesn't compete with content. */
+  scrollbar-width: thin;
+  scrollbar-color: rgb(var(--v-theme-surface-light)) transparent;
+  /* Pad-right so the scrollbar gutter doesn't squeeze card borders. */
+  padding-right: 4px;
+}
 .fc-prov__card {
   border: 1px solid rgb(var(--v-theme-surface-light));
   border-radius: 6px; padding: 10px 12px; margin-bottom: 10px;