feat(onchain-zaps): rich NoteCompose render for kind 8333

Adds RenderOnchainZap, dispatched from RenderNoteRow alongside
RenderLnZap. The card shows a pulsing Bitcoin badge, sender→recipient
avatars, big sats amount in Bitcoin orange, an animated 'ON-CHAIN'
pill, a live confirmation pill (Verifying → In mempool → Confirmed at
block N) sourced from LocalCache.onchainBackend.getTx, and a
tap-to-copy mempool.space tx link.

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

@@ -149,6 +149,7 @@ import com.vitorpamplona.amethyst.ui.note.types.RenderNIP90ContentDiscoveryRespo
 import com.vitorpamplona.amethyst.ui.note.types.RenderNIP90Status
 import com.vitorpamplona.amethyst.ui.note.types.RenderNamedSiteEvent
 import com.vitorpamplona.amethyst.ui.note.types.RenderNipContent
+import com.vitorpamplona.amethyst.ui.note.types.RenderOnchainZap
 import com.vitorpamplona.amethyst.ui.note.types.RenderPinListEvent
 import com.vitorpamplona.amethyst.ui.note.types.RenderPoll
 import com.vitorpamplona.amethyst.ui.note.types.RenderPostApproval
@@ -294,6 +295,7 @@ import com.vitorpamplona.quartz.nip94FileMetadata.FileHeaderEvent
 import com.vitorpamplona.quartz.nip99Classifieds.ClassifiedsEvent
 import com.vitorpamplona.quartz.nipA0VoiceMessages.BaseVoiceEvent
 import com.vitorpamplona.quartz.nipA4PublicMessages.PublicMessageEvent
+import com.vitorpamplona.quartz.nipBCOnchainZaps.zap.OnchainZapEvent
 import com.vitorpamplona.quartz.nipC0CodeSnippets.CodeSnippetEvent
 import com.vitorpamplona.quartz.nipC7Chats.ChatEvent
 import kotlinx.coroutines.Dispatchers
@@ -945,6 +947,10 @@ private fun RenderNoteRow(
             RenderLnZap(baseNote, backgroundColor, accountViewModel, nav)
         }
 
+        is OnchainZapEvent -> {
+            RenderOnchainZap(baseNote, backgroundColor, accountViewModel, nav)
+        }
+
         is LiveActivitiesClipEvent -> {
             RenderChatClip(baseNote, accountViewModel, nav)
         }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/types/OnchainZapEvent.kt

@@ -0,0 +1,425 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.ui.note.types
+
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.animation.core.LinearEasing
+import androidx.compose.animation.core.RepeatMode
+import androidx.compose.animation.core.animateFloat
+import androidx.compose.animation.core.infiniteRepeatable
+import androidx.compose.animation.core.rememberInfiniteTransition
+import androidx.compose.animation.core.tween
+import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.MutableState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.draw.drawBehind
+import androidx.compose.ui.draw.scale
+import androidx.compose.ui.graphics.Brush
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.PathEffect
+import androidx.compose.ui.graphics.StrokeCap
+import androidx.compose.ui.graphics.StrokeJoin
+import androidx.compose.ui.graphics.drawscope.Stroke
+import androidx.compose.ui.platform.LocalClipboard
+import androidx.compose.ui.text.font.FontFamily
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import com.vitorpamplona.amethyst.commons.icons.symbols.Icon
+import com.vitorpamplona.amethyst.commons.icons.symbols.MaterialSymbols
+import com.vitorpamplona.amethyst.model.LocalCache
+import com.vitorpamplona.amethyst.model.Note
+import com.vitorpamplona.amethyst.ui.components.util.setText
+import com.vitorpamplona.amethyst.ui.navigation.navs.INav
+import com.vitorpamplona.amethyst.ui.note.UserPicture
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
+import com.vitorpamplona.amethyst.ui.theme.Size16Modifier
+import com.vitorpamplona.amethyst.ui.theme.Size25dp
+import com.vitorpamplona.amethyst.ui.theme.bitcoinColor
+import com.vitorpamplona.quartz.nipBCOnchainZaps.chain.BitcoinTx
+import com.vitorpamplona.quartz.nipBCOnchainZaps.zap.OnchainZapEvent
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import java.text.NumberFormat
+
+private const val MEMPOOL_TX_URL = "https://mempool.space/tx/"
+
+@Composable
+fun RenderOnchainZap(
+    note: Note,
+    backgroundColor: MutableState<Color>,
+    accountViewModel: AccountViewModel,
+    nav: INav,
+) {
+    val event = note.event as? OnchainZapEvent ?: return
+    val sender = note.author?.pubkeyHex ?: event.pubKey
+    val recipient = event.recipient() ?: return
+    val sats = event.claimedAmountInSats() ?: 0L
+    val txid = event.txid()
+    val message = event.content.takeIf { it.isNotBlank() }
+
+    val orange = MaterialTheme.colorScheme.bitcoinColor
+
+    // Async chain lookup so we can show a real "Confirmed at block N" or
+    // "In mempool…" pill rather than a sender-claimed status. Null = backend
+    // not configured, or fetch failed — we just show the sender-claimed sats
+    // and skip the pill.
+    var tx by remember(txid) { mutableStateOf<BitcoinTx?>(null) }
+    if (txid != null) {
+        LaunchedEffect(txid) {
+            val backend = LocalCache.onchainBackend ?: return@LaunchedEffect
+            runCatching {
+                withContext(Dispatchers.IO) { backend.getTx(txid) }
+            }.onSuccess { tx = it }
+        }
+    }
+
+    Box(
+        modifier =
+            Modifier
+                .fillMaxWidth()
+                .clip(RoundedCornerShape(14.dp))
+                .background(
+                    Brush.linearGradient(
+                        colors =
+                            listOf(
+                                orange.copy(alpha = 0.16f),
+                                orange.copy(alpha = 0.04f),
+                            ),
+                    ),
+                ).padding(horizontal = 12.dp, vertical = 10.dp),
+    ) {
+        Column(verticalArrangement = Arrangement.spacedBy(8.dp)) {
+            HeaderRow(
+                sender = sender,
+                recipient = recipient,
+                orange = orange,
+                accountViewModel = accountViewModel,
+                nav = nav,
+            )
+
+            AmountRow(sats = sats, orange = orange)
+
+            ConfirmationPill(tx = tx, hasTxid = txid != null, orange = orange)
+
+            if (txid != null) {
+                TxidRow(txid = txid, orange = orange)
+            }
+
+            message?.let {
+                Text(
+                    text = it,
+                    style = MaterialTheme.typography.bodyMedium,
+                    color = MaterialTheme.colorScheme.onSurface,
+                )
+            }
+        }
+    }
+}
+
+@Composable
+private fun HeaderRow(
+    sender: String,
+    recipient: String,
+    orange: Color,
+    accountViewModel: AccountViewModel,
+    nav: INav,
+) {
+    Row(
+        verticalAlignment = Alignment.CenterVertically,
+        horizontalArrangement = Arrangement.spacedBy(8.dp),
+    ) {
+        PulsingBitcoinBadge(orange)
+        UserPicture(sender, Size25dp, Modifier, accountViewModel, nav)
+        Icon(
+            symbol = MaterialSymbols.AutoMirrored.ArrowForwardIos,
+            contentDescription = null,
+            tint = orange,
+            modifier = Size16Modifier,
+        )
+        UserPicture(recipient, Size25dp, Modifier, accountViewModel, nav)
+
+        Spacer(Modifier.weight(1f))
+
+        OnchainPill(orange)
+    }
+}
+
+@Composable
+private fun PulsingBitcoinBadge(orange: Color) {
+    val pulse = rememberInfiniteTransition(label = "btcPulse")
+    val scale by pulse.animateFloat(
+        initialValue = 0.92f,
+        targetValue = 1.08f,
+        animationSpec =
+            infiniteRepeatable(
+                animation = tween(1200, easing = LinearEasing),
+                repeatMode = RepeatMode.Reverse,
+            ),
+        label = "btcScale",
+    )
+    val glow by pulse.animateFloat(
+        initialValue = 0.25f,
+        targetValue = 0.55f,
+        animationSpec =
+            infiniteRepeatable(
+                animation = tween(1200, easing = LinearEasing),
+                repeatMode = RepeatMode.Reverse,
+            ),
+        label = "btcGlow",
+    )
+
+    Box(
+        contentAlignment = Alignment.Center,
+        modifier =
+            Modifier
+                .size(32.dp)
+                .drawBehind {
+                    drawCircle(
+                        brush =
+                            Brush.radialGradient(
+                                colors = listOf(orange.copy(alpha = glow), Color.Transparent),
+                            ),
+                        radius = size.minDimension / 2f,
+                    )
+                },
+    ) {
+        Box(
+            modifier =
+                Modifier
+                    .size(24.dp)
+                    .scale(scale)
+                    .clip(CircleShape)
+                    .background(orange),
+            contentAlignment = Alignment.Center,
+        ) {
+            Icon(
+                symbol = MaterialSymbols.CurrencyBitcoin,
+                contentDescription = "Bitcoin",
+                tint = Color.White,
+                modifier = Modifier.size(18.dp),
+            )
+        }
+    }
+}
+
+@Composable
+private fun OnchainPill(orange: Color) {
+    val infinite = rememberInfiniteTransition(label = "pillDash")
+    val phase by infinite.animateFloat(
+        initialValue = 0f,
+        targetValue = 40f,
+        animationSpec =
+            infiniteRepeatable(
+                animation = tween(2500, easing = LinearEasing),
+                repeatMode = RepeatMode.Restart,
+            ),
+        label = "pillPhase",
+    )
+
+    Box(
+        modifier =
+            Modifier
+                .drawBehind {
+                    val brush =
+                        Brush.sweepGradient(
+                            colors =
+                                listOf(
+                                    orange,
+                                    orange.copy(alpha = 0.4f),
+                                    orange,
+                                ),
+                        )
+                    drawRoundRect(
+                        brush = brush,
+                        style =
+                            Stroke(
+                                width = 1.4.dp.toPx(),
+                                cap = StrokeCap.Round,
+                                join = StrokeJoin.Round,
+                                pathEffect = PathEffect.dashPathEffect(floatArrayOf(8f, 6f), phase),
+                            ),
+                        cornerRadius =
+                            androidx.compose.ui.geometry
+                                .CornerRadius(10.dp.toPx()),
+                    )
+                }.padding(horizontal = 8.dp, vertical = 3.dp),
+    ) {
+        Text(
+            text = "ON-CHAIN",
+            style = MaterialTheme.typography.labelSmall,
+            color = orange,
+            fontWeight = FontWeight.Bold,
+        )
+    }
+}
+
+@Composable
+private fun AmountRow(
+    sats: Long,
+    orange: Color,
+) {
+    Row(verticalAlignment = Alignment.Bottom, horizontalArrangement = Arrangement.spacedBy(6.dp)) {
+        Text(
+            text = NumberFormat.getNumberInstance().format(sats),
+            style = MaterialTheme.typography.displaySmall,
+            fontWeight = FontWeight.ExtraBold,
+            color = orange,
+        )
+        Text(
+            text = "sats",
+            style = MaterialTheme.typography.titleSmall,
+            color = orange,
+            modifier = Modifier.padding(bottom = 6.dp),
+        )
+    }
+}
+
+@Composable
+private fun ConfirmationPill(
+    tx: BitcoinTx?,
+    hasTxid: Boolean,
+    orange: Color,
+) {
+    AnimatedVisibility(visible = hasTxid) {
+        val confirmations = tx?.confirmations ?: -1
+        val (label, color) =
+            when {
+                tx == null -> "Verifying on chain…" to orange.copy(alpha = 0.75f)
+                confirmations <= 0 -> "In mempool — pending confirmation" to orange
+                confirmations < 6 -> "Confirmed · $confirmations conf" to orange
+                else ->
+                    "Confirmed · ${tx.blockHeight?.let { "block $it" } ?: "$confirmations conf"}" to
+                        MaterialTheme.colorScheme.primary
+            }
+
+        Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(6.dp)) {
+            if (tx == null || confirmations <= 0) {
+                PulsingDot(color)
+            } else {
+                Icon(
+                    symbol = MaterialSymbols.Block,
+                    contentDescription = null,
+                    tint = color,
+                    modifier = Size16Modifier,
+                )
+            }
+            Text(
+                text = label,
+                style = MaterialTheme.typography.labelMedium,
+                color = color,
+                fontWeight = FontWeight.SemiBold,
+            )
+        }
+    }
+}
+
+@Composable
+private fun PulsingDot(color: Color) {
+    val infinite = rememberInfiniteTransition(label = "dotPulse")
+    val alpha by infinite.animateFloat(
+        initialValue = 0.35f,
+        targetValue = 1f,
+        animationSpec =
+            infiniteRepeatable(
+                animation = tween(900, easing = LinearEasing),
+                repeatMode = RepeatMode.Reverse,
+            ),
+        label = "dotAlpha",
+    )
+    Box(
+        modifier =
+            Modifier
+                .size(8.dp)
+                .clip(CircleShape)
+                .background(color.copy(alpha = alpha)),
+    )
+}
+
+@Composable
+private fun TxidRow(
+    txid: String,
+    orange: Color,
+) {
+    val clipboard = LocalClipboard.current
+    val scope = rememberCoroutineScope()
+    val short = remember(txid) { "${txid.take(10)}…${txid.takeLast(8)}" }
+
+    Row(
+        verticalAlignment = Alignment.CenterVertically,
+        horizontalArrangement = Arrangement.spacedBy(6.dp),
+        modifier =
+            Modifier
+                .clip(RoundedCornerShape(6.dp))
+                .clickable {
+                    scope.launch { clipboard.setText("$MEMPOOL_TX_URL$txid") }
+                }.padding(vertical = 2.dp),
+    ) {
+        Text(
+            text = "tx",
+            style = MaterialTheme.typography.labelSmall,
+            color = orange,
+            fontWeight = FontWeight.Bold,
+        )
+        Text(
+            text = short,
+            style = MaterialTheme.typography.bodySmall,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+            fontFamily = FontFamily.Monospace,
+            maxLines = 1,
+            overflow = TextOverflow.Ellipsis,
+            modifier = Modifier.weight(1f, fill = false),
+        )
+        Spacer(Modifier.width(2.dp))
+        Icon(
+            symbol = MaterialSymbols.ContentCopy,
+            contentDescription = "Copy tx link",
+            tint = orange,
+            modifier = Modifier.size(14.dp),
+        )
+        Spacer(Modifier.height(0.dp))
+    }
+}