Auto-name teams on claim and harden owner-assignment logic

- Add claimTeam() model function that atomically sets ownerId + name in
  a single DB write, replacing the previous two-step assignTeamOwner +
  renameTeam pattern that could leave partial state on failure
- Rename team to "Team <username>" (fallback: displayName, then "Member")
  when a user joins via invite link or an admin assigns a team owner
- Fetch the user record before claiming the team in both paths so we fail
  fast with a clear error rather than silently skipping the rename
- Guard against assigning an already-owned team in the admin settings
  action (closes #107, closes #76)
- Show owner username below team name in draft order settings UI;
  teams with an owner but no matching user record display "Unknown"

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/models/team.ts

@@ -83,6 +83,14 @@ export async function assignTeamOwner(
   return await updateTeam(id, { ownerId });
 }
 
+export async function claimTeam(
+  id: string,
+  ownerId: string,
+  name: string
+): Promise<Team> {
+  return await updateTeam(id, { ownerId, name });
+}
+
 export async function removeTeamOwner(id: string): Promise<Team> {
   return await updateTeam(id, { ownerId: null });
 }

app/routes/i.$inviteCode.tsx

@@ -8,8 +8,9 @@ import {
   findLeagueById,
   findCommissionersByLeagueId,
   findAvailableTeams,
-  assignTeamOwner,
+  claimTeam,
   isUserLeagueMember,
+  findUserByClerkId,
 } from "~/models";
 import { Button } from "~/components/ui/button";
 import {
@@ -94,8 +95,16 @@ export async function action(args: Route.ActionArgs) {
     throw new Response("No available teams in this league", { status: 400 });
   }
 
-  // Assign the first available team to the user
-  await assignTeamOwner(availableTeams[0].id, userId);
+  // Look up user before claiming to fail fast and get their name
+  const user = await findUserByClerkId(userId);
+  if (!user) {
+    throw new Response("User account not found. Please try again.", { status: 500 });
+  }
+
+  // Claim the first available team, setting owner and name atomically
+  const team = availableTeams[0];
+  const teamName = `Team ${user.username || user.displayName || "Member"}`;
+  await claimTeam(team.id, userId, teamName);
 
   // Redirect to league page
   return redirect(`/leagues/${season.leagueId}?joined=true`);

app/routes/leagues/$leagueId.settings.tsx

@@ -14,7 +14,7 @@ import {
   removeCommissionerByLeagueAndUser,
 } from "~/models/commissioner";
 import { findCurrentSeasonWithSports, updateSeason } from "~/models/season";
-import { findTeamsBySeasonId, deleteTeam, removeTeamOwner, assignTeamOwner } from "~/models/team";
+import { findTeamsBySeasonId, deleteTeam, removeTeamOwner, claimTeam } from "~/models/team";
 import { findAllUsers, findUserByClerkId, isUserAdminByClerkId } from "~/models/user";
 import { unlinkSportFromSeason, linkMultipleSportsToSeason } from "~/models/season-sport";
 import { findAllSportsSeasons } from "~/models/sports-season";
@@ -361,16 +361,30 @@ export async function action(args: Route.ActionArgs) {
       return { error: "Only admins can assign team owners" };
     }
 
+    // Look up user before assigning to fail fast and get their name
+    const assignedUser = await findUserByClerkId(userClerkId);
+    if (!assignedUser) {
+      return { error: "User not found. Please try again." };
+    }
+
     // Check if user is already assigned to a team in this season
     const teams = await findTeamsBySeasonId(season.id);
     const userAlreadyHasTeam = teams.some(team => team.ownerId === userClerkId);
-    
+
     if (userAlreadyHasTeam) {
       return { error: "This user is already assigned to a team in this league" };
     }
 
+    // Check if the target team already has an owner
+    const targetTeam = teams.find(team => team.id === teamId);
+    if (targetTeam?.ownerId) {
+      return { error: "This team already has an owner. Remove the current owner first." };
+    }
+
     try {
-      await assignTeamOwner(teamId, userClerkId);
+      const teamName = `Team ${assignedUser.username || assignedUser.displayName || "Member"}`;
+      await claimTeam(teamId, userClerkId, teamName);
+
       return { success: true, message: "Owner assigned successfully" };
     } catch (error) {
       console.error("Error assigning team owner:", error);
@@ -1132,6 +1146,9 @@ export default function LeagueSettings({ loaderData, actionData }: Route.Compone
                           </div>
                           <div className="flex-1">
                             <p className="font-medium">{team.name}</p>
+                            {team.ownerId && (
+                              <p className="text-xs text-muted-foreground">{ownerMap[team.ownerId] ?? "Unknown"}</p>
+                            )}
                           </div>
                           {canEditDraftOrder && (
                             <div className="flex gap-1">