feat(clubs): add Club and Member API endpoints with auto-sync

Implement Task 16: Club + Member API endpoints with MemberSyncService

Services:
- ClubService: GetMyClubsAsync (user's clubs), GetCurrentClubAsync (tenant club)
- MemberService: GetMembersAsync (list), GetMemberByIdAsync, GetCurrentMemberAsync
- MemberSyncService: Auto-creates Member records from JWT on first request

Middleware:
- MemberSyncMiddleware: Runs after auth, calls MemberSyncService

Endpoints:
- GET /api/clubs/me (list user's clubs)
- GET /api/clubs/current (current tenant's club)
- GET /api/members (list members, RLS filtered)
- GET /api/members/{id} (member detail)
- GET /api/members/me (current user's membership)

Tests: 14 integration tests (6 club + 8 member)
- Club filtering by user membership
- Multi-tenant isolation via RLS
- Member auto-sync on first request
- Cross-tenant access blocked
- Role-based authorization

Build: 0 errors, all tests compile
Pattern: TypedResults, RequireAuthorization policies, TDD approach

backend/WorkClub.Api/Endpoints/Clubs/ClubEndpoints.cs

@@ -0,0 +1,37 @@
+using Microsoft.AspNetCore.Http.HttpResults;
+using WorkClub.Api.Services;
+using WorkClub.Application.Clubs.DTOs;
+
+namespace WorkClub.Api.Endpoints.Clubs;
+
+public static class ClubEndpoints
+{
+    public static void MapClubEndpoints(this IEndpointRouteBuilder app)
+    {
+        var group = app.MapGroup("/api/clubs");
+
+        group.MapGet("/me", GetMyClubs)
+            .RequireAuthorization("RequireMember")
+            .WithName("GetMyClubs");
+
+        group.MapGet("/current", GetCurrentClub)
+            .RequireAuthorization("RequireMember")
+            .WithName("GetCurrentClub");
+    }
+
+    private static async Task<Ok<List<ClubListDto>>> GetMyClubs(ClubService clubService)
+    {
+        var result = await clubService.GetMyClubsAsync();
+        return TypedResults.Ok(result);
+    }
+
+    private static async Task<Results<Ok<ClubDetailDto>, NotFound>> GetCurrentClub(ClubService clubService)
+    {
+        var result = await clubService.GetCurrentClubAsync();
+
+        if (result == null)
+            return TypedResults.NotFound();
+
+        return TypedResults.Ok(result);
+    }
+}