feat(nests): wire nest chat composer to NestNewMessageViewModel

Completes the copy approach started in 57ebded6:

  - NestEditFieldRow.kt: copy of EditFieldRow, drops the BackHandler
    (the activity owns back; draft auto-save runs on every keystroke
    so there is nothing to flush) and points every callback at
    NestNewMessageViewModel.
  - NestFileUploadDialog.kt: copy of ChannelFileUploadDialog, header
    shows the room host's avatar + room name from the loaded
    MeetingSpaceEvent.
  - NestChatPanel.kt: replaces the slim inline composer with
    NestEditFieldRow + NestNewMessageViewModel. Chat message list is
    still rendered from NestViewModel.chat — the new VM is scoped to
    *editing and sending* messages only, per the brief.
  - NestNewMessageViewModel.sendPostSync: switched from
    signAndSendPrivately(template, emptySet()) to
    signAndComputeBroadcast(template) so messages actually reach the
    user's default relays (matches the original slim composer's
    behaviour).

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/nests/room/NestChatPanel.kt

@@ -51,8 +51,8 @@ import com.vitorpamplona.amethyst.model.Note
 import com.vitorpamplona.amethyst.ui.navigation.navs.BouncingIntentNav
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.chats.feed.ChatroomMessageCompose
-import com.vitorpamplona.amethyst.ui.screen.loggedIn.chats.publicChannels.send.ChannelNewMessageViewModel
-import com.vitorpamplona.amethyst.ui.screen.loggedIn.chats.publicChannels.send.EditFieldRow
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.nests.room.send.NestEditFieldRow
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.nests.room.send.NestNewMessageViewModel
 import com.vitorpamplona.amethyst.ui.stringRes
 import com.vitorpamplona.quartz.nip53LiveActivities.chat.LiveActivitiesChatMessageEvent
 import com.vitorpamplona.quartz.nip53LiveActivities.meetingSpaces.MeetingSpaceEvent
@@ -63,45 +63,21 @@ import com.vitorpamplona.quartz.nip53LiveActivities.meetingSpaces.MeetingSpaceEv
  * per-message renderer that NIP-53 live-stream chat uses
  * ([ChatroomMessageCompose]).
  *
- * Composer is the same [EditFieldRow] used by every other public-chat
- * surface in the app, so we get @-mention picker, file/image/video
- * upload, reply preview, draft auto-save, emoji suggestions, content
- * warnings, expiration, geohash, and zap-split forwarding for free.
+ * The composer is owned by a separate [NestNewMessageViewModel] —
+ * scoped to *editing and sending* chat messages only — so we get
+ * @-mention picker, file/image/video upload, reply preview, NIP-37
+ * draft auto-save, emoji suggestions, content warnings, expiration,
+ * geohash, and zap-split forwarding for the nest chat field. The
+ * message list itself is still driven from the [NestViewModel] so
+ * presence / reactions / chat all share a single lifecycle.
  *
- * To stay aligned with the rest of the app, the composer is backed by
- * a [ChannelNewMessageViewModel] loaded with a [LiveActivitiesChannel]
- * keyed by the meeting space's address. `ChannelNewMessageViewModel.
- * createTemplate()` already handles the `LiveActivitiesChannel` →
- * `LiveActivitiesChatMessageEvent` path: when `channel.info` is null
- * (we never populate it for kind-30312 — it's typed to the kind-30311
- * `LiveActivitiesEvent`), it falls through to the
- * `LiveActivitiesChatMessageEvent.message(message, channel.toATag())`
- * branch, which produces exactly the same event the original slim
- * composer was emitting.
- *
- * Data flow: messages still arrive via the existing nest pipeline
- * (`RoomChatFilterAssemblerSubscription` → `NestViewModel.onChatEvent`
- * → `viewModel.chat`). The composer emits via
- * `account.signAndSendPrivately(template, channelRelays)` inside
- * `ChannelNewMessageViewModel.sendPostSync`, which lands on the same
- * relays the listener subscribes to, so the user sees their own
- * message immediately when it round-trips. Drafts are stored as
- * NIP-37 wrap events through the standard account draft pipeline —
- * they do not pollute `viewModel.chat` because that flow only accepts
- * kind-1311 events.
- *
- * Navigation: the activity has no Compose NavHost in scope. Taps that
- * resolve to a NIP-19 entity (profile, quoted note, hashtag, addressable
- * channel) are dispatched through [BouncingIntentNav] — a `nostr:` URI
- * Intent at MainActivity. Anything that doesn't have a `nostr:` URI is
- * a no-op for now. The audio room keeps running in its own task while
- * the user explores; back from MainActivity returns to the room.
- *
- * The composer's default back-press handler from [EditFieldRow] would
- * try to `nav.popBack()` (a no-op on [BouncingIntentNav]) and clear
- * the field — both wrong inside an Activity-scoped chat panel where
- * back means "leave the room". We pass `interceptBackPress = false`
- * so system back continues to flow to the activity.
+ * Navigation: the activity has no Compose NavHost in scope. Taps
+ * that resolve to a NIP-19 entity (profile, quoted note, hashtag,
+ * addressable channel) are dispatched through [BouncingIntentNav]
+ * — a `nostr:` URI Intent at MainActivity. Anything that doesn't
+ * have a `nostr:` URI is a no-op for now. The audio room keeps
+ * running in its own task while the user explores; back from
+ * MainActivity returns to the room.
  */
 @Composable
 internal fun ColumnScope.NestChatPanel(
@@ -115,16 +91,12 @@ internal fun ColumnScope.NestChatPanel(
     val scope = rememberCoroutineScope()
     val nav = remember(context, scope) { BouncingIntentNav(context, scope) }
 
-    val channel =
-        remember(event) {
-            accountViewModel.checkGetOrCreateLiveActivityChannel(event.address())
-        }
     val routeForLastRead = remember(event) { "NestChat/${event.address().toValue()}" }
 
-    val channelScreenModel: ChannelNewMessageViewModel =
+    val nestScreenModel: NestNewMessageViewModel =
         composeViewModel(key = "Nest/${event.address().toValue()}")
-    channelScreenModel.init(accountViewModel)
-    channelScreenModel.load(channel)
+    nestScreenModel.init(accountViewModel)
+    nestScreenModel.load(event)
 
     Column(modifier = modifier.fillMaxWidth()) {
         Box(modifier = Modifier.fillMaxWidth().weight(1f, fill = true)) {
@@ -141,19 +113,18 @@ internal fun ColumnScope.NestChatPanel(
                     routeForLastRead = routeForLastRead,
                     accountViewModel = accountViewModel,
                     nav = nav,
-                    onWantsToReply = channelScreenModel::reply,
+                    onWantsToReply = nestScreenModel::reply,
                 )
             }
         }
 
         Spacer(Modifier.height(8.dp))
 
-        EditFieldRow(
-            channelScreenModel = channelScreenModel,
+        NestEditFieldRow(
+            nestScreenModel = nestScreenModel,
             accountViewModel = accountViewModel,
             onSendNewMessage = {},
             nav = nav,
-            interceptBackPress = false,
         )
     }
 }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/nests/room/send/NestEditFieldRow.kt

@@ -0,0 +1,167 @@
+/*
+ * 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.screen.loggedIn.nests.room.send
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.material3.LocalTextStyle
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextFieldDefaults
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.text.input.KeyboardCapitalization
+import androidx.compose.ui.text.style.TextDirection
+import androidx.compose.ui.unit.dp
+import com.vitorpamplona.amethyst.R
+import com.vitorpamplona.amethyst.ui.actions.MentionPreservingInputTransformation
+import com.vitorpamplona.amethyst.ui.actions.StrippingFailureDialog
+import com.vitorpamplona.amethyst.ui.actions.UrlUserTagOutputTransformation
+import com.vitorpamplona.amethyst.ui.actions.uploads.SelectFromGallery
+import com.vitorpamplona.amethyst.ui.components.ThinPaddingTextField
+import com.vitorpamplona.amethyst.ui.navigation.navs.INav
+import com.vitorpamplona.amethyst.ui.note.creators.emojiSuggestions.ShowEmojiSuggestionList
+import com.vitorpamplona.amethyst.ui.note.creators.userSuggestions.ShowUserSuggestionList
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.chats.utils.DisplayReplyingToNote
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.chats.utils.ThinSendButton
+import com.vitorpamplona.amethyst.ui.stringRes
+import com.vitorpamplona.amethyst.ui.theme.EditFieldBorder
+import com.vitorpamplona.amethyst.ui.theme.EditFieldModifier
+import com.vitorpamplona.amethyst.ui.theme.EditFieldTrailingIconModifier
+import com.vitorpamplona.amethyst.ui.theme.SuggestionListDefaultHeightChat
+import com.vitorpamplona.amethyst.ui.theme.placeholderText
+import kotlinx.coroutines.FlowPreview
+
+/**
+ * Mirror of `EditFieldRow` for the nest-room composer. Uses
+ * [NestNewMessageViewModel] which is scoped to a single
+ * [com.vitorpamplona.quartz.nip53LiveActivities.meetingSpaces.MeetingSpaceEvent]
+ * and only emits kind-1311 chat messages.
+ *
+ * Renders, top-to-bottom: stripping-failure dialog, reply preview,
+ * file-upload dialog, @-mention picker, emoji suggestions, and the
+ * text field with gallery picker + send button.
+ *
+ * Differences from the channel `EditFieldRow`:
+ *  - No `BackHandler`: the nest chat panel lives inside an Activity
+ *    that owns its own back behaviour (leave room / enter PiP). The
+ *    composer's draft auto-save runs on every text change via
+ *    [NestNewMessageViewModel.draftTag], so there is nothing to flush
+ *    on back press.
+ */
+@OptIn(FlowPreview::class)
+@Composable
+fun NestEditFieldRow(
+    nestScreenModel: NestNewMessageViewModel,
+    accountViewModel: AccountViewModel,
+    onSendNewMessage: suspend () -> Unit,
+    nav: INav,
+) {
+    StrippingFailureDialog(nestScreenModel.strippingFailureConfirmation)
+
+    nestScreenModel.replyTo.value?.let {
+        DisplayReplyingToNote(it, accountViewModel, nav) {
+            nestScreenModel.clearReply()
+        }
+    }
+
+    nestScreenModel.uploadState?.let { uploading ->
+        uploading.multiOrchestrator?.let {
+            NestFileUploadDialog(
+                nestScreenModel = nestScreenModel,
+                state = uploading,
+                onUpload = onSendNewMessage,
+                onCancel = uploading::reset,
+                accountViewModel = accountViewModel,
+                nav = nav,
+            )
+        }
+    }
+
+    Column(
+        modifier = EditFieldModifier,
+    ) {
+        nestScreenModel.userSuggestions?.let {
+            ShowUserSuggestionList(
+                it,
+                nestScreenModel::autocompleteWithUser,
+                accountViewModel,
+                SuggestionListDefaultHeightChat,
+            )
+        }
+
+        nestScreenModel.emojiSuggestions?.let {
+            ShowEmojiSuggestionList(
+                it,
+                nestScreenModel::autocompleteWithEmoji,
+                nestScreenModel::autocompleteWithEmojiUrl,
+                SuggestionListDefaultHeightChat,
+            )
+        }
+
+        ThinPaddingTextField(
+            state = nestScreenModel.message,
+            onTextChanged = { nestScreenModel.onMessageChanged() },
+            inputTransformation = MentionPreservingInputTransformation,
+            keyboardOptions =
+                KeyboardOptions.Default.copy(
+                    capitalization = KeyboardCapitalization.Sentences,
+                ),
+            shape = EditFieldBorder,
+            modifier = Modifier.fillMaxWidth(),
+            placeholder = {
+                Text(
+                    text = stringRes(R.string.reply_here),
+                    color = MaterialTheme.colorScheme.placeholderText,
+                )
+            },
+            textStyle = LocalTextStyle.current.copy(textDirection = TextDirection.Content),
+            trailingIcon = {
+                ThinSendButton(
+                    isActive =
+                        nestScreenModel.message.text.isNotBlank() && !nestScreenModel.isUploadingImage,
+                    modifier = EditFieldTrailingIconModifier,
+                ) {
+                    nestScreenModel.sendPost(onSendNewMessage)
+                }
+            },
+            leadingIcon = {
+                SelectFromGallery(
+                    isUploading = nestScreenModel.isUploadingImage,
+                    tint = MaterialTheme.colorScheme.placeholderText,
+                    modifier = Modifier.height(32.dp).padding(start = 2.dp),
+                    onImageChosen = nestScreenModel::pickedMedia,
+                )
+            },
+            colors =
+                TextFieldDefaults.colors(
+                    focusedIndicatorColor = Color.Transparent,
+                    unfocusedIndicatorColor = Color.Transparent,
+                ),
+            outputTransformation = UrlUserTagOutputTransformation(MaterialTheme.colorScheme.primary),
+        )
+    }
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/nests/room/send/NestFileUploadDialog.kt

@@ -0,0 +1,108 @@
+/*
+ * 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.screen.loggedIn.nests.room.send
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import com.vitorpamplona.amethyst.model.LocalCache
+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.screen.loggedIn.chats.utils.ChatFileUploadDialog
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.chats.utils.ChatFileUploadState
+import com.vitorpamplona.amethyst.ui.theme.Size34dp
+
+/**
+ * Mirror of `ChannelFileUploadDialog` for nest chat. Wraps the
+ * generic [ChatFileUploadDialog] with a header showing the host
+ * avatar + the room name pulled from the [NestNewMessageViewModel]'s
+ * loaded [com.vitorpamplona.quartz.nip53LiveActivities.meetingSpaces.MeetingSpaceEvent].
+ */
+@Composable
+fun NestFileUploadDialog(
+    nestScreenModel: NestNewMessageViewModel,
+    state: ChatFileUploadState,
+    onUpload: suspend () -> Unit,
+    onCancel: () -> Unit,
+    accountViewModel: AccountViewModel,
+    nav: INav,
+) {
+    val room = nestScreenModel.room ?: return
+    val context = LocalContext.current
+
+    val host = remember(room.pubKey) { LocalCache.getOrCreateUser(room.pubKey) }
+    val title = room.room().orEmpty()
+
+    ChatFileUploadDialog(
+        state,
+        title = {
+            Row(verticalAlignment = Alignment.CenterVertically) {
+                UserPicture(
+                    user = host,
+                    size = Size34dp,
+                    accountViewModel = accountViewModel,
+                    nav = nav,
+                )
+
+                Column(
+                    modifier =
+                        Modifier
+                            .padding(start = 10.dp)
+                            .height(35.dp)
+                            .weight(1f),
+                    verticalArrangement = Arrangement.Center,
+                ) {
+                    Row(verticalAlignment = Alignment.CenterVertically) {
+                        Text(
+                            text = title,
+                            maxLines = 1,
+                            overflow = TextOverflow.Ellipsis,
+                        )
+                    }
+                }
+            }
+        },
+        upload = {
+            nestScreenModel.upload(
+                onError = accountViewModel.toastManager::toast,
+                context = context,
+                onceUploaded = onUpload,
+            )
+
+            accountViewModel.account.settings.changeDefaultFileServer(state.selectedServer)
+            accountViewModel.account.settings.changeStripLocationOnUpload(state.stripMetadata)
+        },
+        onCancel,
+        accountViewModel,
+        nav,
+    )
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/nests/room/send/NestNewMessageViewModel.kt

@@ -297,7 +297,11 @@ open class NestNewMessageViewModel :
         val version = draftTag.current
         cancel()
 
-        accountViewModel.account.signAndSendPrivately(template, emptySet())
+        // Broadcast to the user's default relays — the nest has no
+        // dedicated relay set the way a public-chat channel does, so
+        // this matches what the original slim composer was doing via
+        // `account.signAndComputeBroadcast(...)`.
+        accountViewModel.account.signAndComputeBroadcast(template)
         accountViewModel.viewModelScope.launch(Dispatchers.IO) {
             accountViewModel.account.deleteDraftIgnoreErrors(version)
         }