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/ImageViewer.vue

@@ -92,7 +92,16 @@ let prevBodyOverflow = null
 // own keystrokes.
 function onKeyDown(ev) {
   if (ev.key === 'Escape') {
-    if (isTextEntry(ev.target)) return
+    // Escape closes the modal even from inside a text input — that's
+    // the universal "get me out of here" expectation, and the
+    // autofocused tag-entry field would otherwise trap focus with no
+    // visible escape (operator-flagged 2026-06-01). EXCEPTION: when a
+    // nested Vuetify overlay is open (v-menu autocomplete dropdown,
+    // FandomPicker v-dialog, per-suggestion 3-dot menu), let that
+    // overlay's own Esc handling fire instead of closing the whole
+    // modal mid-interaction. Vuetify marks open overlays with
+    // `.v-overlay--active`.
+    if (document.querySelector('.v-overlay--active')) return
     ev.preventDefault()
     emit('close')
   } else if (ev.key === 'ArrowLeft') {