feat(live-chat): display live stream clips (kind 1313) inline

Add a Quartz LiveActivitiesClipEvent for zap.stream's kind 1313 clip
convention, parsing the `a` tag (stream address), `p` tag (host), `r`
tag (video URL), and `title` tag. Register it in EventFactory, subscribe
in the live-activity chat filter, and route clips into the source
LiveActivitiesChannel cache. Render clips as an accent-colored card
showing "X created a clip" with the title and an inline video player
for the clip's playable URL.

https://claude.ai/code/session_01WJA5PvDABegBYUu6h42YZi

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip53LiveActivities/clip/LiveActivitiesClipEvent.kt

@@ -0,0 +1,114 @@
+/*
+ * 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.clip
+
+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.PubKeyHintProvider
+import com.vitorpamplona.quartz.nip01Core.hints.types.AddressHint
+import com.vitorpamplona.quartz.nip01Core.hints.types.PubKeyHint
+import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
+import com.vitorpamplona.quartz.nip01Core.tags.aTag.ATag
+import com.vitorpamplona.quartz.nip01Core.tags.aTag.aTag
+import com.vitorpamplona.quartz.nip01Core.tags.people.PTag
+import com.vitorpamplona.quartz.nip01Core.tags.references.ReferenceTag
+import com.vitorpamplona.quartz.nip23LongContent.tags.TitleTag
+import com.vitorpamplona.quartz.nip31Alts.AltTag
+import com.vitorpamplona.quartz.nip53LiveActivities.streaming.LiveActivitiesEvent
+import com.vitorpamplona.quartz.utils.TimeUtils
+
+/**
+ * NIP-53 live stream clip (zap.stream convention, kind 1313).
+ *
+ * A clip is a standalone highlight produced from an ongoing or past live stream.
+ * The event carries:
+ *   - `a`     -> the source stream address (kind 30311)
+ *   - `p`     -> the stream host's pubkey
+ *   - `r`     -> direct playable video URL (MP4/HLS)
+ *   - `title` -> clip title
+ *   - `alt`   -> NIP-31 fallback text
+ *
+ * `content` is an optional free-text caption.
+ */
+@Immutable
+class LiveActivitiesClipEvent(
+    id: HexKey,
+    pubKey: HexKey,
+    createdAt: Long,
+    tags: Array<Array<String>>,
+    content: String,
+    sig: HexKey,
+) : Event(id, pubKey, createdAt, KIND, tags, content, sig),
+    AddressHintProvider,
+    PubKeyHintProvider {
+    override fun addressHints(): List<AddressHint> = tags.mapNotNull(ATag::parseAsHint)
+
+    override fun linkedAddressIds(): List<String> = tags.mapNotNull(ATag::parseAddressId)
+
+    override fun pubKeyHints(): List<PubKeyHint> = tags.mapNotNull(PTag::parseAsHint)
+
+    override fun linkedPubKeys(): List<HexKey> = tags.mapNotNull(PTag::parseKey)
+
+    fun activity(): ATag? =
+        tags
+            .asSequence()
+            .mapNotNull(ATag::parse)
+            .firstOrNull { it.kind == LiveActivitiesEvent.KIND }
+
+    fun activityAddress(): Address? = activity()?.let { Address(it.kind, it.pubKeyHex, it.dTag) }
+
+    fun host(): HexKey? = tags.firstNotNullOfOrNull(PTag::parseKey)
+
+    fun videoUrl(): String? = tags.firstNotNullOfOrNull(ReferenceTag::parse)
+
+    fun title(): String? = tags.firstNotNullOfOrNull(TitleTag::parse)
+
+    companion object {
+        const val KIND = 1313
+        const val ALT = "Live activity clip"
+
+        /**
+         * Builds an event template for a clip. Typically published by the clip-authoring backend
+         * on behalf of a viewer, but can also be published directly by a client.
+         */
+        fun build(
+            activity: EventHintBundle<LiveActivitiesEvent>,
+            videoUrl: String,
+            title: String,
+            host: HexKey = activity.event.pubKey,
+            caption: String = "",
+            createdAt: Long = TimeUtils.now(),
+            initializer: TagArrayBuilder<LiveActivitiesClipEvent>.() -> Unit = {},
+        ) = eventTemplate(KIND, caption, createdAt) {
+            aTag(ATag(activity.event.kind, activity.event.pubKey, activity.event.dTag(), activity.relay))
+            add(PTag.assemble(host, null))
+            add(ReferenceTag.assemble(videoUrl))
+            add(TitleTag.assemble(title))
+            add(AltTag.assemble(ALT))
+            initializer()
+        }
+    }
+}

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

@@ -165,6 +165,7 @@ import com.vitorpamplona.quartz.nip52Calendar.appt.time.CalendarTimeSlotEvent
 import com.vitorpamplona.quartz.nip52Calendar.calendar.CalendarEvent
 import com.vitorpamplona.quartz.nip52Calendar.rsvp.CalendarRSVPEvent
 import com.vitorpamplona.quartz.nip53LiveActivities.chat.LiveActivitiesChatMessageEvent
+import com.vitorpamplona.quartz.nip53LiveActivities.clip.LiveActivitiesClipEvent
 import com.vitorpamplona.quartz.nip53LiveActivities.meetingSpaces.MeetingRoomEvent
 import com.vitorpamplona.quartz.nip53LiveActivities.meetingSpaces.MeetingSpaceEvent
 import com.vitorpamplona.quartz.nip53LiveActivities.presence.MeetingRoomPresenceEvent
@@ -437,6 +438,7 @@ class EventFactory {
                 KindMuteSetEvent.KIND -> KindMuteSetEvent(id, pubKey, createdAt, tags, content, sig)
                 LabeledBookmarkListEvent.KIND -> LabeledBookmarkListEvent(id, pubKey, createdAt, tags, content, sig)
                 LiveActivitiesChatMessageEvent.KIND -> LiveActivitiesChatMessageEvent(id, pubKey, createdAt, tags, content, sig)
+                LiveActivitiesClipEvent.KIND -> LiveActivitiesClipEvent(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)