Use sorted username dropdown for character owner editing

RpgRoller/Components/Pages/Workspace.razor.cs

@@ -89,6 +89,20 @@ public partial class Workspace : IAsyncDisposable
         }
     }
 
+    private async Task LoadKnownUsernamesAsync()
+    {
+        try
+        {
+            var usernames = await ApiClient.RequestAsync<IReadOnlyList<string>>("GET", "/api/users/usernames");
+            KnownUsernames = usernames.OrderBy(username => username, StringComparer.OrdinalIgnoreCase).ToList();
+        }
+        catch (ApiRequestException ex)
+        {
+            KnownUsernames = [];
+            SetStatus(ex.Message, true);
+        }
+    }
+
     private async Task<bool> ReloadAuthenticatedSessionAsync(Guid? preferredCampaignId)
     {
         var me = await TryGetMeAsync();
@@ -291,8 +305,11 @@ public partial class Workspace : IAsyncDisposable
         ShowCreateCharacterModal = true;
     }
 
-    private void OpenEditCharacterModal(CharacterSummary character)
+    private async Task OpenEditCharacterModal(CharacterSummary character)
     {
+        if (IsCurrentUserGm)
+            await LoadKnownUsernamesAsync();
+
         EditingCharacterId = character.Id;
         EditCharacterInitialModel = new()
         {
@@ -659,6 +676,7 @@ public partial class Workspace : IAsyncDisposable
         CampaignLog = [];
         SelectedCharacterId = null;
         LastRoll = null;
+        KnownUsernames = [];
         ShowCreateCharacterModal = false;
         ShowEditCharacterModal = false;
         CanEditCharacterOwner = false;
@@ -723,6 +741,7 @@ public partial class Workspace : IAsyncDisposable
     private List<RulesetDefinition> Rulesets { get; set; } = [];
     private Guid? SelectedCharacterId { get; set; }
     private RollResult? LastRoll { get; set; }
+    private List<string> KnownUsernames { get; set; } = [];
     private string RollVisibility { get; set; } = "public";
 
     private bool IsMutating { get; set; }