feat: render a lone zap notification as a full note, not a bare card

The single-zap/single-nutzap branch of MultiSetCompose dropped the bare
RenderLnZap/RenderNutzap activity card straight into the feed, with no
author column on the left, so it didn't read like the surrounding notes.

Reuse NoteCompose on the zap-receipt note instead: it wraps the same zap
card as the note body and gives it the standard note chrome — author
picture on the left, username header, reactions row. Padding is handed to
NoteCompose for this branch so it isn't doubled against the card column.

NoteCompose's author column previously resolved baseNote.author, which for
a kind-9735 zap receipt is the recipient's lightning provider (the signer),
not the zapper. Resolve the sender from the embedded zap request the same
way the thread's master note already does, so the picture on the left is
the actual zapper.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Cg8mHZDCfGmGAVDaeJxPFz

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/MultiSetCompose.kt

@@ -87,8 +87,6 @@ import com.vitorpamplona.amethyst.ui.navigation.routes.Route
 import com.vitorpamplona.amethyst.ui.navigation.routes.authorRouteFor
 import com.vitorpamplona.amethyst.ui.navigation.routes.routeFor
 import com.vitorpamplona.amethyst.ui.note.elements.NoteDropDownMenu
-import com.vitorpamplona.amethyst.ui.note.types.RenderLnZap
-import com.vitorpamplona.amethyst.ui.note.types.RenderNutzap
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.notifications.CombinedZap
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.notifications.MultiSetCard
@@ -185,29 +183,39 @@ fun MultiSetCompose(
                     },
                     onLongClick = { popupExpanded.value = true },
                 ).padding(
-                    start = 12.dp,
-                    end = 12.dp,
-                    top = 10.dp,
-                    bottom = if (isLargeCard) 10.dp else 0.dp,
+                    // The large-card branch renders through NoteCompose, which applies
+                    // its own 12dp/10dp note padding; let it own the inset there so we
+                    // don't double it up. The gallery branch keeps the card's padding.
+                    start = if (isLargeCard) 0.dp else 12.dp,
+                    end = if (isLargeCard) 0.dp else 12.dp,
+                    top = if (isLargeCard) 0.dp else 10.dp,
+                    bottom = 0.dp,
                 )
         }
 
     Column(modifier = columnModifier) {
         when {
+            // Render the lone zap/nutzap as a full note (author picture on the left,
+            // the zap card as its body) by reusing NoteCompose on the receipt note,
+            // instead of dropping the bare activity card into the feed.
             singleZap != null ->
-                RenderLnZap(
-                    note = singleZap.response,
+                NoteCompose(
+                    baseNote = singleZap.response,
+                    routeForLastRead = null,
+                    isHiddenFeed = showHidden,
                     quotesLeft = 1,
-                    backgroundColor = backgroundColor,
+                    parentBackgroundColor = backgroundColor,
                     accountViewModel = accountViewModel,
                     nav = nav,
                 )
 
             singleNutzap != null ->
-                RenderNutzap(
-                    note = singleNutzap,
+                NoteCompose(
+                    baseNote = singleNutzap,
+                    routeForLastRead = null,
+                    isHiddenFeed = showHidden,
                     quotesLeft = 1,
-                    backgroundColor = backgroundColor,
+                    parentBackgroundColor = backgroundColor,
                     accountViewModel = accountViewModel,
                     nav = nav,
                 )

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/NoteCompose.kt

@@ -2010,6 +2010,16 @@ fun RenderAuthorImages(
         } else {
             NoteAuthorPicture(baseNote, Size55dp, accountViewModel = accountViewModel, nav = nav)
         }
+    } else if (noteEvent is LnZapEvent) {
+        // Zap receipts are signed by the recipient's lightning provider; show the
+        // sender from the embedded zap request instead of the service key, matching
+        // how the thread's master note resolves the author.
+        val zapSender = observeZapSender(baseNote, accountViewModel).value
+        if (zapSender != null) {
+            UserPicture(zapSender, Size55dp, accountViewModel = accountViewModel, nav = nav)
+        } else {
+            NoteAuthorPicture(baseNote, Size55dp, accountViewModel = accountViewModel, nav = nav)
+        }
     } else {
         NoteAuthorPicture(baseNote, Size55dp, accountViewModel = accountViewModel, nav = nav)
     }