Groups verified, and stop calling the user a number

Groups now driven end to end on Android against relay.flamenet.io: created
"Testers" with a member, it appears in the list, it SURVIVES a full `pm clear`
and re-sign-in (restored from the relay), it opens, and a message sends into
it. This was one of the original asks and had never been exercised.

Two things it turned up:

🔴 **The relay's 401 also blamed the passphrase.** The AccountsClient fix in
the previous commit was correct and incomplete: `describe()` mapped
`RelayException.Unauthorized` to "That handle or passphrase isn't right" too,
and that is the path that actually fires when a relay token ages out. Same
lie, same consequence — a user changing a password that was never wrong. It
now says the session expired, which is what happened.

⚠️ **You are never in your own buddy list**, so every "find the name among the
buddies" fallback rendered the signed-in user as `user 31`. The group row read
"user 31, fnreviewbeta". `Phase.SignedIn` now carries its own `userId` and both
fallbacks say "You". Verified live: the row reads "You, fnreviewbeta".

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

app/src/main/kotlin/io/flamenet/messenger/app/ChatScreens.kt

@@ -364,8 +364,12 @@ fun ColumnScope.GroupsSection(
                     fontWeight = if (thread in phase.unread) FontWeight.Bold else null,
                 )
                 Text(
+                    // "You" first: you are a member of your own group and are
+                    // not in your own buddy list, so this used to read
+                    // "user 31, fnreviewbeta".
                     group.memberIds.joinToString(", ") { id ->
-                        phase.buddies.firstOrNull { it.userId == id }
+                        if (id == phase.userId) "You"
+                        else phase.buddies.firstOrNull { it.userId == id }
                             ?.let { b -> b.displayName.ifBlank { b.handle } }
                             ?: "user $id"
                     },

app/src/main/kotlin/io/flamenet/messenger/app/MessengerViewModel.kt

@@ -38,6 +38,15 @@ class MessengerViewModel(app: Application) : AndroidViewModel(app) {
 
         data class SignedIn(
             val handle: String,
+            /**
+             * This account's own id.
+             *
+             * ⚠️ Needed because **you are never in your own buddy list**, so
+             * every "look the name up among the buddies" fallback rendered you
+             * as `user 31` — visible on the group row, which listed its members
+             * as "user 31, fnreviewbeta".
+             */
+            val userId: Long,
             val deviceId: String,
             val relay: String,
             val status: String,
@@ -214,6 +223,7 @@ class MessengerViewModel(app: Application) : AndroidViewModel(app) {
                     )
                     stored to Phase.SignedIn(
                         handle = credential.username,
+                        userId = credential.userId,
                         deviceId = stored.deviceId,
                         relay = SiteConfig(credential.relayBaseUrl).host,
                         status = "Signed in on this device.",
@@ -326,6 +336,7 @@ class MessengerViewModel(app: Application) : AndroidViewModel(app) {
 
         return Phase.SignedIn(
             handle = account.username,
+            userId = account.userId,
             deviceId = device.deviceId,
             relay = config.host,
             status = "Registered with ${preKeys.size} one-time prekeys published.",
@@ -776,7 +787,8 @@ class MessengerViewModel(app: Application) : AndroidViewModel(app) {
         getApplication<Application>().getSharedPreferences("calls", android.content.Context.MODE_PRIVATE)
 
     private fun nameFor(phase: Phase.SignedIn, userId: Long): String =
-        phase.buddies.firstOrNull { it.userId == userId }
+        if (userId == phase.userId) "You"
+        else phase.buddies.firstOrNull { it.userId == userId }
             ?.let { it.displayName.ifBlank { it.handle } } ?: "user $userId"
 
     /**
@@ -1171,7 +1183,13 @@ class MessengerViewModel(app: Application) : AndroidViewModel(app) {
         is AccountsClient.Failure.HandleTaken -> "That handle is already taken."
         is AccountsClient.Failure.RateLimited -> "Too many attempts. Wait a few minutes."
         is AccountsClient.Failure.Transport -> failure.message.orEmpty()
-        is RelayException.Unauthorized -> "That handle or passphrase isn't right."
+        // ⚠️ NOT "that passphrase is wrong". The relay rejects a TOKEN, which
+        // the user never typed and cannot check. Telling them their passphrase
+        // is wrong when their session merely aged out sends them off to change
+        // a password that was fine — observed on a send ten hours after a
+        // successful sign-in.
+        is RelayException.Unauthorized ->
+            "Your session expired. Sign out and back in to keep going."
         is RelayException.NotFound -> "This server doesn't look like a Flamenet relay."
         is RelayException.RateLimited -> "Too many attempts. Wait a few minutes."
         is Vault.Corrupt -> "This phone's stored keys could not be read."