feat: mark conversation participants with an 'In this chat' chip in mention suggestions

Renders a small chip on suggestion rows whose pubkey is in the
suggestion state's priorityPubkeys set, unless the caller supplies
its own trailingContent. Priority keys only reorder and label the
users that already matched the search — they never inject results.

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/creators/userSuggestions/ShowUserSuggestionList.kt

@@ -25,13 +25,16 @@ import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.LazyListState
 import androidx.compose.foundation.lazy.itemsIndexed
 import androidx.compose.foundation.lazy.rememberLazyListState
+import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.LocalTextStyle
 import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
@@ -43,6 +46,7 @@ import androidx.compose.ui.text.AnnotatedString
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import com.vitorpamplona.amethyst.R
 import com.vitorpamplona.amethyst.commons.model.nip05DnsIdentifiers.Nip05State
 import com.vitorpamplona.amethyst.model.LocalCache
 import com.vitorpamplona.amethyst.model.User
@@ -52,6 +56,7 @@ import com.vitorpamplona.amethyst.ui.note.ClickableUserPicture
 import com.vitorpamplona.amethyst.ui.note.ObserveAndRenderNIP05VerifiedSymbol
 import com.vitorpamplona.amethyst.ui.note.UsernameDisplay
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
+import com.vitorpamplona.amethyst.ui.stringRes
 import com.vitorpamplona.amethyst.ui.theme.DividerThickness
 import com.vitorpamplona.amethyst.ui.theme.Font14SP
 import com.vitorpamplona.amethyst.ui.theme.NIP05IconSize
@@ -116,13 +121,23 @@ fun WatchResponses(
     val suggestions by userSuggestions.results.collectAsStateWithLifecycle(emptyList())
 
     if (suggestions.isNotEmpty()) {
+        // Snapshot once per result list, not per row.
+        val priority = remember(suggestions) { userSuggestions.priorityPubkeys() }
+
         LazyColumn(
             contentPadding = PaddingValues(top = 10.dp),
             modifier = modifier,
             state = listState,
         ) {
             itemsIndexed(suggestions, key = { _, item -> item.pubkeyHex }) { _, item ->
-                UserLine(item, accountViewModel, trailingContent) { onSelect(item) }
+                val trailing =
+                    trailingContent
+                        ?: if (item.pubkeyHex in priority) {
+                            { InThisChatChip() }
+                        } else {
+                            null
+                        }
+                UserLine(item, accountViewModel, trailing) { onSelect(item) }
                 HorizontalDivider(
                     thickness = DividerThickness,
                 )
@@ -133,6 +148,22 @@ fun WatchResponses(
     }
 }
 
+@Composable
+private fun InThisChatChip() {
+    Surface(
+        shape = RoundedCornerShape(12.dp),
+        color = MaterialTheme.colorScheme.surfaceVariant,
+    ) {
+        Text(
+            text = stringRes(R.string.user_suggestion_in_this_chat),
+            style = MaterialTheme.typography.labelSmall,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+            maxLines = 1,
+            modifier = Modifier.padding(horizontal = 8.dp, vertical = 4.dp),
+        )
+    }
+}
+
 @Composable
 fun UserLine(
     baseUser: User,

amethyst/src/main/res/values/strings.xml

@@ -214,6 +214,7 @@
     <string name="voice_anonymize_description">Alters your voice pitch. Note: basic pitch changes can potentially be reversed by determined listeners.</string>
     <string name="user_does_not_have_a_lightning_address_setup_to_receive_sats">User does not have a lightning address set up to receive sats</string>
     <string name="reply_here">"reply here… "</string>
+    <string name="user_suggestion_in_this_chat">In this chat</string>
     <string name="copies_the_note_id_to_the_clipboard_for_sharing">Copies the Note ID to the clipboard for sharing in Nostr</string>
     <string name="copy_channel_id_note_to_the_clipboard">Copy Channel ID (Note) to the Clipboard</string>
     <string name="edits_the_channel_metadata">Edits the Channel Metadata</string>