feat(ui): grounding overlay leads with the hovered tag, crop origin as subtext (#1206)

The overlay label showed only the crop origin (booru:head / panel / person-m).
Put the hovered TAG on top as the headline and demote the crop origin to a small,
dimmed, monospace subline — the tag is what you're evaluating; the origin is just
provenance. Threads the tag name through the fcSuggestionHover payload ({g, tag})
from both setters (SuggestionItem for suggestions, TagChip for applied chips).

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

frontend/src/components/modal/SuggestionItem.vue

@@ -85,7 +85,7 @@ defineEmits(['accept', 'alias', 'remove-alias', 'dismiss', 'undismiss'])
 // it highlights that region. Provided by ImageViewer/Explore; a no-op elsewhere.
 const hover = inject('fcSuggestionHover', null)
 function onEnter () {
-  if (hover) hover.value = { g: props.suggestion.grounding ?? null }
+  if (hover) hover.value = { g: props.suggestion.grounding ?? null, tag: props.suggestion.display_name }
 }
 function onLeave () {
   if (hover) hover.value = null