feat(live-chat): display live stream raids (kind 1312) inline

Add a Quartz LiveActivitiesRaidEvent for zap.stream's kind 1312 raid
convention with root/mention a-tag markers. Wire it into the event
factory, subscribe to it in the live-activity chat filter, and route
received raids into both source and target LiveActivitiesChannel caches
so viewers on either side see the notification. Render raids as an
accent-colored pill showing "X is raiding Y" that navigates to the
target stream when tapped.

https://claude.ai/code/session_01WJA5PvDABegBYUu6h42YZi

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip53LiveActivities/raid/LiveActivitiesRaidEvent.kt

@@ -0,0 +1,115 @@
+/*
+ * 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.quartz.nip53LiveActivities.raid
+
+import androidx.compose.runtime.Immutable
+import com.vitorpamplona.quartz.nip01Core.core.Address
+import com.vitorpamplona.quartz.nip01Core.core.Event
+import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip01Core.hints.AddressHintProvider
+import com.vitorpamplona.quartz.nip01Core.hints.EventHintBundle
+import com.vitorpamplona.quartz.nip01Core.hints.types.AddressHint
+import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
+import com.vitorpamplona.quartz.nip01Core.tags.aTag.ATag
+import com.vitorpamplona.quartz.nip53LiveActivities.streaming.LiveActivitiesEvent
+import com.vitorpamplona.quartz.utils.TimeUtils
+
+/**
+ * NIP-53 live stream raid (zap.stream convention, kind 1312).
+ *
+ * A raid is authored by the source streamer to redirect viewers to another live
+ * stream. The event carries two `a` tags referencing NIP-53 Live Activities
+ * (kind 30311) differentiated by NIP-10-style markers at position 3:
+ *   - "root"    -> the source stream (the raid is being sent FROM)
+ *   - "mention" -> the target stream (the raid is being sent TO)
+ *
+ * The `content` is a free-text raid message from the source streamer.
+ */
+@Immutable
+class LiveActivitiesRaidEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: Array<Array<String>>,
+    content: String,
+    sig: HexKey,
+) : Event(id, pubKey, createdAt, KIND, tags, content, sig),
+    AddressHintProvider {
+    override fun addressHints(): List<AddressHint> = tags.mapNotNull(ATag::parseAsHint)
+
+    override fun linkedAddressIds(): List<String> = tags.mapNotNull(ATag::parseAddressId)
+
+    fun fromActivity(): ATag? = findActivity(MARKER_ROOT)
+
+    fun toActivity(): ATag? = findActivity(MARKER_MENTION)
+
+    fun fromAddress(): Address? = fromActivity()?.let { Address(it.kind, it.pubKeyHex, it.dTag) }
+
+    fun toAddress(): Address? = toActivity()?.let { Address(it.kind, it.pubKeyHex, it.dTag) }
+
+    private fun findActivity(marker: String): ATag? =
+        tags
+            .asSequence()
+            .filter { it.size > 3 && it[0] == ATag.TAG_NAME && it[3] == marker }
+            .mapNotNull(ATag::parse)
+            .firstOrNull { it.kind == LiveActivitiesEvent.KIND }
+
+    companion object {
+        const val KIND = 1312
+        const val ALT = "Live activity raid"
+        const val MARKER_ROOT = "root"
+        const val MARKER_MENTION = "mention"
+
+        /**
+         * Builds an event template for a raid. Sender must be the host of the `from` stream.
+         *
+         * @param from    source stream (the one currently live that is being ended/redirected)
+         * @param to      target stream (where viewers should be redirected)
+         * @param message raid announcement text
+         */
+        fun build(
+            from: EventHintBundle<LiveActivitiesEvent>,
+            to: EventHintBundle<LiveActivitiesEvent>,
+            message: String = "",
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<LiveActivitiesRaidEvent>.() -> Unit = {},
+        ) = eventTemplate(KIND, message, createdAt) {
+            addMarkedATag(from, MARKER_ROOT)
+            addMarkedATag(to, MARKER_MENTION)
+            initializer()
+        }
+
+        private fun TagArrayBuilder<LiveActivitiesRaidEvent>.addMarkedATag(
+            bundle: EventHintBundle<LiveActivitiesEvent>,
+            marker: String,
+        ) {
+            val relayUrl = bundle.relay?.url.orEmpty()
+            val addressId =
+                Address.assemble(
+                    LiveActivitiesEvent.KIND,
+                    bundle.event.pubKey,
+                    bundle.event.dTag(),
+                )
+            add(arrayOf(ATag.TAG_NAME, addressId, relayUrl, marker))
+        }
+    }
+}

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/utils/EventFactory.kt

@@ -168,6 +168,7 @@ import com.vitorpamplona.quartz.nip53LiveActivities.chat.LiveActivitiesChatMessa
 import com.vitorpamplona.quartz.nip53LiveActivities.meetingSpaces.MeetingRoomEvent
 import com.vitorpamplona.quartz.nip53LiveActivities.meetingSpaces.MeetingSpaceEvent
 import com.vitorpamplona.quartz.nip53LiveActivities.presence.MeetingRoomPresenceEvent
+import com.vitorpamplona.quartz.nip53LiveActivities.raid.LiveActivitiesRaidEvent
 import com.vitorpamplona.quartz.nip53LiveActivities.streaming.LiveActivitiesEvent
 import com.vitorpamplona.quartz.nip54Wiki.WikiNoteEvent
 import com.vitorpamplona.quartz.nip56Reports.ReportEvent
@@ -437,6 +438,7 @@ class EventFactory {
                 LabeledBookmarkListEvent.KIND -> LabeledBookmarkListEvent(id, pubKey, createdAt, tags, content, sig)
                 LiveActivitiesChatMessageEvent.KIND -> LiveActivitiesChatMessageEvent(id, pubKey, createdAt, tags, content, sig)
                 LiveActivitiesEvent.KIND -> LiveActivitiesEvent(id, pubKey, createdAt, tags, content, sig)
+                LiveActivitiesRaidEvent.KIND -> LiveActivitiesRaidEvent(id, pubKey, createdAt, tags, content, sig)
                 LnZapEvent.KIND -> LnZapEvent(id, pubKey, createdAt, tags, content, sig)
                 LnZapPaymentRequestEvent.KIND -> LnZapPaymentRequestEvent(id, pubKey, createdAt, tags, content, sig)
                 LnZapPaymentResponseEvent.KIND -> LnZapPaymentResponseEvent(id, pubKey, createdAt, tags, content, sig)