fix(ui): tag-rail no longer scroll-jumps on accept/reject; keep suggestions clear of the toast

- TagAutocomplete: focus the inner input with preventScroll so handing focus
  back after an accept/reject stops yanking the rail up to the field (which sits
  above the suggestions list — you had to scroll back down every time). Applies
  to both the image modal and the Explore rail.
- ExploreView: pad the right rail's scroll bottom (88px) so the bottom-right
  snackbar floats over empty space instead of covering the last suggestions and
  their accept/reject controls.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CDgx8bQS5YrGRK76v8HUnM

frontend/src/views/ExploreView.vue

@@ -350,10 +350,14 @@ onUnmounted(() => {
 }
 .fc-ex__artist { padding: 10px 16px 0; font-weight: 600; }
 
-/* Right rail = the modal's tag panel, hosted on the anchor. */
+/* Right rail = the modal's tag panel, hosted on the anchor. The bottom padding
+   keeps the scrollable content from reaching the viewport floor, so the
+   bottom-right snackbar floats over empty space instead of covering the last
+   suggestions / their accept-reject controls (operator-flagged 2026-07-06). */
 .fc-ex__rail {
   background: rgb(var(--v-theme-surface));
   overflow-y: auto;
+  padding-bottom: 88px;
 }
 
 .fc-ex__spinner {