feat(integrity): ImageViewer badge for corrupt/unverified status

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

frontend/src/components/modal/ImageViewer.vue

@@ -11,6 +11,13 @@
         <v-icon>mdi-close</v-icon>
       </button>
 
+      <v-chip
+        v-if="integrityBadge"
+        :color="integrityBadge.color"
+        class="fc-viewer__integrity"
+        size="x-small" variant="flat"
+      >{{ integrityBadge.label }}</v-chip>
+
       <button
         class="fc-viewer__nav fc-viewer__nav--prev"
         :disabled="!modal.canPrev" @click="modal.goPrev()" aria-label="Previous"
@@ -68,6 +75,14 @@ const isVideo = computed(() =>
   modal.current?.mime && modal.current.mime.startsWith('video/')
 )
 
+const integrityBadge = computed(() => {
+  const s = modal.current?.integrity_status
+  if (s === 'corrupt') return { color: 'error', label: 'Corrupt' }
+  if (s === 'failed_verification')
+    return { color: 'warning', label: 'Unverified' }
+  return null
+})
+
 let prevBodyOverflow = null
 onMounted(async () => {
   prevBodyOverflow = document.body.style.overflow
@@ -128,6 +143,9 @@ function isTextEntry(el) {
 }
 .fc-viewer__nav:disabled { opacity: 0.3; cursor: not-allowed; }
 .fc-viewer__close { top: 16px; right: 16px; transform: none; }
+.fc-viewer__integrity {
+  position: absolute; top: 72px; right: 16px; z-index: 3;
+}
 .fc-viewer__nav--prev { left: 16px; transform: translateY(-50%); }
 .fc-viewer__nav--next { right: 16px; transform: translateY(-50%); }
 .fc-viewer__body {