fix(concord): show the 64-byte name cap instead of silently dropping the edit

Community, channel and access-role names are capped at 64 UTF-8 bytes (CORD-02
§6). The actions refused a longer name, but the forms took any length, so a
long rename or channel create simply did nothing.

The name fields now show a "used / 64 bytes" counter that turns red past the
cap, and Create / Save / Rename stay disabled until the name fits.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

commonsUI/src/commonMain/composeResources/values/strings.xml

@@ -591,6 +591,7 @@
     <string name="concord_invite_revoke_explainer">Anyone still holding this link will no longer be able to join. People who already joined with it stay in the community. This can't be undone.</string>
     <string name="concord_invite_revoke_confirm">Revoke</string>
     <string name="concord_invite_revoking">Revoking…</string>
+    <string name="concord_name_budget">%1$d / %2$d bytes</string>
     <string name="concord_invite_revoke_privatize_warning">This is the community's last live invite link. Revoking it makes the community Private and rotates its keys, so only current members keep access.</string>
     <string name="concord_invite_revoked_privatized">Link revoked. The community is now Private and its keys were rotated.</string>
     <string name="concord_invite_revoked_privatize_pending">Link revoked. The community is now Private, but its keys were not rotated: an admin who can ban members needs to rotate them.</string>

commonsUI/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/ui/screen/loggedIn/chats/publicChannels/concord/ConcordChannelListScreen.kt

@@ -851,6 +851,8 @@ private fun ConcordChannelEditDialog(
                     onValueChange = { name = it },
                     singleLine = true,
                     label = { Text(stringRes(Res.string.concord_channel_name_label)) },
+                    isError = !concordNameFits(name),
+                    supportingText = { ConcordNameBudget(name) },
                     modifier = Modifier.fillMaxWidth(),
                 )
                 // A new channel may be Private (CORD-03): its own key, and an access Role — the
@@ -872,6 +874,8 @@ private fun ConcordChannelEditDialog(
                             singleLine = true,
                             placeholder = { Text(name.trim()) },
                             label = { Text(stringRes(Res.string.concord_channel_access_role_label)) },
+                            isError = !concordNameFits(roleName),
+                            supportingText = { if (roleName.isNotBlank()) ConcordNameBudget(roleName) },
                             modifier = Modifier.fillMaxWidth(),
                         )
                     }
@@ -880,8 +884,9 @@ private fun ConcordChannelEditDialog(
         },
         confirmButton = {
             TextButton(
-                enabled = name.isNotBlank(),
-                onClick = { if (name.isNotBlank()) onConfirm(name.trim(), makePrivate, roleName.trim().ifBlank { null }) },
+                // Past the 64-byte cap every reader drops the edition, so the action would silently no-op.
+                enabled = name.isNotBlank() && concordNameFits(name) && concordNameFits(roleName),
+                onClick = { if (name.isNotBlank() && concordNameFits(name) && concordNameFits(roleName)) onConfirm(name.trim(), makePrivate, roleName.trim().ifBlank { null }) },
             ) {
                 Text(
                     stringRes(

commonsUI/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/ui/screen/loggedIn/chats/publicChannels/concord/ConcordCreateScreen.kt

@@ -147,7 +147,7 @@ fun ConcordCreateScreen(
                         }
                     }
                 },
-                enabled = name.value.isNotBlank() && !working,
+                enabled = name.value.isNotBlank() && concordNameFits(name.value) && !working,
                 modifier = Modifier.fillMaxWidth().padding(top = 8.dp),
             ) {
                 Text(stringRes(Res.string.concord_create_action))

commonsUI/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/ui/screen/loggedIn/chats/publicChannels/concord/ConcordEditScreen.kt

@@ -202,7 +202,7 @@ fun ConcordEditScreen(
                         if (ok) nav.popBack()
                     }
                 },
-                enabled = name.value.isNotBlank() && !working,
+                enabled = name.value.isNotBlank() && concordNameFits(name.value) && !working,
                 modifier = Modifier.fillMaxWidth().padding(top = 8.dp),
             ) {
                 Text(stringRes(Res.string.concord_edit_save))

commonsUI/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/ui/screen/loggedIn/chats/publicChannels/concord/ConcordMetadataForm.kt

@@ -69,6 +69,7 @@ import com.vitorpamplona.amethyst.commons.resources.concord_create_icon_hint
 import com.vitorpamplona.amethyst.commons.resources.concord_create_name
 import com.vitorpamplona.amethyst.commons.resources.concord_create_title
 import com.vitorpamplona.amethyst.commons.resources.concord_edit_banner_hint
+import com.vitorpamplona.amethyst.commons.resources.concord_name_budget
 import com.vitorpamplona.amethyst.commons.resources.failed_to_upload_media_no_details
 import com.vitorpamplona.amethyst.commons.resources.remove
 import com.vitorpamplona.amethyst.commons.ui.actions.uploads.GallerySelectSingle
@@ -85,6 +86,7 @@ import com.vitorpamplona.amethyst.commons.ui.stringRes
 import com.vitorpamplona.amethyst.commons.ui.theme.MediumRelayIconModifier
 import com.vitorpamplona.amethyst.commons.viewmodels.AccountViewModel
 import com.vitorpamplona.quartz.concord.cord02Community.ImagePointer
+import com.vitorpamplona.quartz.concord.cord04Roles.ConcordLimits
 import com.vitorpamplona.quartz.nip01Core.relay.normalizer.NormalizedRelayUrl
 import com.vitorpamplona.quartz.nip01Core.relay.normalizer.displayUrl
 import com.vitorpamplona.quartz.utils.Log
@@ -130,6 +132,8 @@ fun ConcordMetadataFields(
             modifier = Modifier.fillMaxWidth(),
             singleLine = true,
             label = { Text(stringRes(Res.string.concord_create_name)) },
+            isError = !concordNameFits(name.value),
+            supportingText = { ConcordNameBudget(name.value) },
         )
         OutlinedTextField(
             value = about.value,
@@ -142,6 +146,21 @@ fun ConcordMetadataFields(
     }
 }
 
+/**
+ * Whether [name] fits the protocol-wide name cap (CORD-02 §6: 64 UTF-8 bytes, for the Community,
+ * Channels and Roles). Every reader drops an edition past it, so a form must not submit one.
+ */
+fun concordNameFits(name: String): Boolean = ConcordLimits.nameFits(name.trim())
+
+/** A text field's `used / 64` byte counter for a Concord name, in the error color once over the cap. */
+@Composable
+fun ConcordNameBudget(name: String) {
+    Text(
+        stringRes(Res.string.concord_name_budget, ConcordLimits.utf8Size(name.trim()), ConcordLimits.NAME_MAX_BYTES),
+        color = if (concordNameFits(name)) MaterialTheme.colorScheme.onSurfaceVariant else MaterialTheme.colorScheme.error,
+    )
+}
+
 /**
  * The circular community-icon hero: shows the current (decrypted) icon over a stable robohash
  * placeholder, and on tap opens the photo picker → encrypts + uploads the chosen image and updates