fix: route tournament calls through backend gateway

Use relative /api/tournament path instead of hardcoded
http://141.37.123.132:8086. The browser was hitting the external
tournament-server directly with the user's RS256 token, which it
rejects. Routing through our backend lets it publish to the native
server with the auto-registered director token.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/services/tournament.service.ts

@@ -2,7 +2,6 @@ import { Injectable, inject } from '@angular/core';
 import { HttpClient, HttpHeaders } from '@angular/common/http';
 import { Observable } from 'rxjs';
 import { Tournament, TournamentList, RoundPairings } from '../models/tournament.models';
-import { environment } from '../../environments/environment';
 
 export interface CreateTournamentForm {
   name: string;
@@ -15,7 +14,7 @@ export interface CreateTournamentForm {
 @Injectable({ providedIn: 'root' })
 export class TournamentService {
   private readonly http = inject(HttpClient);
-  private readonly base = `${(environment.tournamentServerUrl ?? '').replace(/\/+$/, '')}/api/tournament`;
+  private readonly base = '/api/tournament';
 
   list(): Observable<TournamentList> {
     return this.http.get<TournamentList>(this.base);