Simplify edit state and surface edit errors to user

- Combine editingId + editingName into single editing: { id, name } | null state object
- Extract cancelEdit() helper called in 3 places instead of repeating setEditing(null)
- Tag all update-name action responses with intent: "update-name" so errors can be
  identified and routed correctly
- Show update-name errors inline below the edit input
- Guard single-add and bulk-add error displays against showing update-name errors

https://claude.ai/code/session_01Q94DWQ1HZEB9PJhGMArU8D

app/routes/admin.sports-seasons.$id.participants.tsx

@@ -69,17 +69,17 @@ export async function action({ request, params }: Route.ActionArgs) {
     const newName = formData.get("newName");
 
     if (typeof participantId !== "string") {
-      return { error: "Invalid participant" };
+      return { error: "Invalid participant", intent: "update-name" };
     }
 
     if (typeof newName !== "string" || !newName.trim()) {
-      return { error: "Name is required" };
+      return { error: "Name is required", intent: "update-name" };
     }
 
     const trimmedName = newName.trim();
     const existing = await findParticipantByName(params.id, trimmedName);
     if (existing && existing.id !== participantId) {
-      return { error: `"${trimmedName}" already exists in this season.` };
+      return { error: `"${trimmedName}" already exists in this season.`, intent: "update-name" };
     }
 
     try {
@@ -87,7 +87,7 @@ export async function action({ request, params }: Route.ActionArgs) {
       return { success: true, intent: "update-name" };
     } catch (error) {
       logger.error("Error updating participant:", error);
-      return { error: "Failed to update participant. Please try again." };
+      return { error: "Failed to update participant. Please try again.", intent: "update-name" };
     }
   }
 
@@ -171,16 +171,16 @@ export async function action({ request, params }: Route.ActionArgs) {
 
 export default function ManageParticipants({ loaderData, actionData }: Route.ComponentProps) {
   const { sportsSeason, participants } = loaderData;
-  const [editingId, setEditingId] = useState<string | null>(null);
+  const [editing, setEditing] = useState<{ id: string; name: string } | null>(null);
-  const [editingName, setEditingName] = useState("");
+
+  const cancelEdit = () => setEditing(null);
 
   // Use success state to reset forms by changing the key
   const formKey = actionData?.success ? Date.now() : 'static';
 
   useEffect(() => {
     if (actionData?.success && actionData?.intent === "update-name") {
-      setEditingId(null);
+      cancelEdit();
-      setEditingName("");
     }
   }, [actionData]);
 
@@ -221,7 +221,7 @@ export default function ManageParticipants({ loaderData, actionData }: Route.Com
                   />
                 </div>
 
-                {actionData?.error && !actionData?.count && (
+                {actionData?.error && !actionData?.count && actionData?.intent !== "update-name" && (
                   <div className="bg-destructive/15 text-destructive px-4 py-3 rounded-md text-sm">
                     {actionData.error}
                   </div>
@@ -267,7 +267,7 @@ export default function ManageParticipants({ loaderData, actionData }: Route.Com
                   </p>
                 </div>
 
-                {actionData?.error && actionData?.count === undefined && (
+                {actionData?.error && actionData?.count === undefined && actionData?.intent !== "update-name" && (
                   <div className="bg-destructive/15 text-destructive px-4 py-3 rounded-md text-sm">
                     {actionData.error}
                   </div>
@@ -318,30 +318,30 @@ export default function ManageParticipants({ loaderData, actionData }: Route.Com
                       {participants.map((participant) => (
                         <TableRow key={participant.id}>
                           <TableCell className="font-medium">
-                            {editingId === participant.id ? (
+                            {editing?.id === participant.id ? (
+                              <div className="space-y-1">
                                 <Input
-                                value={editingName}
+                                  value={editing.name}
-                                onChange={(e) => setEditingName(e.target.value)}
+                                  onChange={(e) => setEditing({ id: participant.id, name: e.target.value })}
                                   className="h-8"
                                   autoFocus
-                                onKeyDown={(e) => {
+                                  onKeyDown={(e) => { if (e.key === "Escape") cancelEdit(); }}
-                                  if (e.key === "Escape") {
-                                    setEditingId(null);
-                                    setEditingName("");
-                                  }
-                                }}
                                 />
+                                {actionData?.error && actionData?.intent === "update-name" && (
+                                  <p className="text-xs text-destructive">{actionData.error}</p>
+                                )}
+                              </div>
                             ) : (
                               participant.name
                             )}
                           </TableCell>
                           <TableCell>
-                            {editingId === participant.id ? (
+                            {editing?.id === participant.id ? (
                               <div className="flex gap-1">
                                 <Form method="post">
                                   <input type="hidden" name="intent" value="update-name" />
                                   <input type="hidden" name="participantId" value={participant.id} />
-                                  <input type="hidden" name="newName" value={editingName} />
+                                  <input type="hidden" name="newName" value={editing.name} />
                                   <Button
                                     type="submit"
                                     variant="ghost"
@@ -356,10 +356,7 @@ export default function ManageParticipants({ loaderData, actionData }: Route.Com
                                   variant="ghost"
                                   size="sm"
                                   className="h-8 w-8 p-0"
-                                  onClick={() => {
+                                  onClick={cancelEdit}
-                                    setEditingId(null);
-                                    setEditingName("");
-                                  }}
                                 >
                                   <X className="h-4 w-4" />
                                 </Button>
@@ -371,10 +368,7 @@ export default function ManageParticipants({ loaderData, actionData }: Route.Com
                                   variant="ghost"
                                   size="sm"
                                   className="h-8 w-8 p-0"
-                                  onClick={() => {
+                                  onClick={() => setEditing({ id: participant.id, name: participant.name })}
-                                    setEditingId(participant.id);
-                                    setEditingName(participant.name);
-                                  }}
                                 >
                                   <Pencil className="h-4 w-4" />
                                 </Button>