feat(events): make favoriting instant (optimistic) + pop animation

The heart took ~1s to fill because toggleBookmark awaited the remote
LNbits signer + relay publish before updating state. Flip local state
optimistically so the heart responds on tap, then sign/publish in the
background and roll back (with an error toast) if it fails. Add a brief
scale pop on the heart when a favorite is added for tactile feedback.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/modules/events/components/BookmarkButton.vue

@@ -1,5 +1,5 @@
 <script setup lang="ts">
-import { computed } from 'vue'
+import { computed, ref, watch } from 'vue'
 import { useRouter } from 'vue-router'
 import { Button } from '@/components/ui/button'
 import { Heart } from 'lucide-vue-next'
@@ -21,7 +21,18 @@ const { isBookmarked, toggleBookmark } = useBookmarks()
 const eventKind = computed(() => props.kind ?? NIP52_KINDS.CALENDAR_TIME_EVENT)
 const bookmarked = computed(() => isBookmarked(eventKind.value, props.pubkey, props.dTag))
 
-function handleToggle() {
+// Brief scale "pop" when a favorite is added, for tactile feedback. The
+// state flip is already optimistic (see useBookmarks), so this fires
+// immediately on tap.
+const popping = ref(false)
+watch(bookmarked, (now, was) => {
+  if (now && !was) {
+    popping.value = true
+    setTimeout(() => (popping.value = false), 220)
+  }
+})
+
+async function handleToggle() {
   if (!isAuthenticated.value) {
     toast.info('Log in to save favorites', {
       action: {
@@ -31,7 +42,10 @@ function handleToggle() {
     })
     return
   }
-  toggleBookmark(eventKind.value, props.pubkey, props.dTag)
+  const ok = await toggleBookmark(eventKind.value, props.pubkey, props.dTag)
+  if (!ok) {
+    toast.error("Couldn't save favorite — please try again")
+  }
 }
 </script>
 
@@ -43,6 +57,9 @@ function handleToggle() {
     :class="bookmarked ? 'text-red-500 hover:text-red-600' : 'text-muted-foreground hover:text-foreground'"
     @click.stop="handleToggle"
   >
-    <Heart class="w-4 h-4" :class="{ 'fill-current': bookmarked }" />
+    <Heart
+      class="w-4 h-4 transition-transform duration-200 ease-out"
+      :class="[{ 'fill-current': bookmarked }, popping ? 'scale-125' : 'scale-100']"
+    />
   </Button>
 </template>

src/modules/events/composables/useBookmarks.ts

@@ -88,9 +88,20 @@ export function useBookmarks() {
 
   /**
    * Toggle bookmark for an event. Publishes updated NIP-51 bookmark list.
+   *
+   * Updates local state OPTIMISTICALLY so the UI (heart fill) responds
+   * instantly, then signs + publishes in the background. Signing routes
+   * through the remote LNbits signer and publishing hits relays, so
+   * awaiting both before flipping state made the heart lag ~1s. On
+   * failure the optimistic change is rolled back. Resolves to whether
+   * the change was persisted.
    */
-  async function toggleBookmark(eventKind: number, pubkey: string, dTag: string) {
-    if (!isAuthenticated.value || !currentUser.value?.pubkey) return
+  async function toggleBookmark(
+    eventKind: number,
+    pubkey: string,
+    dTag: string,
+  ): Promise<boolean> {
+    if (!isAuthenticated.value || !currentUser.value?.pubkey) return false
 
     const coord = `${eventKind}:${pubkey}:${dTag}`
     const newCoords = new Set(state.value.bookmarkedCoords)
@@ -101,6 +112,17 @@ export function useBookmarks() {
       newCoords.add(coord)
     }
 
+    // Optimistic flip — preserve the prior state so we can roll back if
+    // signing or publishing fails. Keep lastEventId/lastCreatedAt until
+    // the real event is confirmed.
+    const prevState = state.value
+    state.value = { bookmarkedCoords: newCoords, lastEventId: prevState.lastEventId }
+    ;(state.value as any).lastCreatedAt = (prevState as any).lastCreatedAt
+
+    function rollback() {
+      state.value = prevState
+    }
+
     // Build and publish updated bookmark list
     const tags: string[][] = Array.from(newCoords).map(c => ['a', c])
 
@@ -116,19 +138,25 @@ export function useBookmarks() {
       signedEvent = await signEventViaLnbits(template)
     } catch (err) {
       console.error('[useBookmarks] signEventViaLnbits failed:', err)
-      return
+      rollback()
+      return false
     }
 
     const relayHub = tryInjectService<any>(SERVICE_TOKENS.RELAY_HUB)
-    if (!relayHub) return
+    if (!relayHub) {
+      rollback()
+      return false
+    }
 
     const result = await relayHub.publishEvent(signedEvent)
     if (result.success > 0) {
-      state.value = {
-        bookmarkedCoords: newCoords,
-        lastEventId: signedEvent.id,
-      }
+      state.value = { bookmarkedCoords: newCoords, lastEventId: signedEvent.id }
+      ;(state.value as any).lastCreatedAt = template.created_at
+      return true
     }
+
+    rollback()
+    return false
   }
 
   onMounted(() => {