feat(web): add private club showcases with membership flow (v3.7.0)

Implements Issue #110: game masters can now publish sessions
exclusively to a club's private showcase, gated behind a
member application and approval flow. Adds a 4-state
publication_mode (None/Catalog/ClubOnly/Both) replacing the
binary is_public, plus a club_memberships table with
Pending/Active/Rejected/Left lifecycle and partial unique
index ensuring a single Active row per (group, player).

Highlights
- V030 migration: club_memberships, publication_mode, drop
  is_public, recreate partial indexes, portfolio_games gains
  publication_mode.
- PublicationMode enum + extensions in GmRelay.Shared.
- ISessionStore gains 12 membership/showcase methods;
  AuthorizedMembershipService owns the membership flow with
  GM-only approve/reject authorization.
- PublicClub / PublicMasterProfile / PublicSession: member-
  aware queries (ClubOnly visible only to Active members).
- New pages: MyClubMemberships (/profile/memberships) and
  ClubApplications (/group/{id}/applications).
- GroupDetails and EditSession switch from a bool toggle to
  a 4-state publication_mode selector.
- NavMenu adds Moji kluby, PublicLayout adds Kluby.

Tests: 4 new test files (PublicationMode, ClubMemberships,
AuthorizedMembershipService, ClubShowcaseSource) + updates
to PublicClubPages, AuthorizedSessionService/Portfolio
service FakeSessionStore, CampaignTemplatesNavigation.
493 tests pass.

Bump version 3.6.0 -> 3.7.0 across Directory.Build.props,
compose.yaml, deploy.yml, NavMenu.razor.

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

src/GmRelay.Web/Components/Pages/MyClubMemberships.razor

@@ -0,0 +1,147 @@
+@page "/profile/memberships"
+@using GmRelay.Web.Services
+@using Microsoft.AspNetCore.Authorization
+@attribute [Authorize]
+@inject AuthorizedMembershipService MembershipService
+@inject NavigationManager Navigation
+
+<PageTitle>Мои клубы — GM-Relay</PageTitle>
+
+<div class="page-container">
+    <ul class="gm-breadcrumb animate-fade-in">
+        <li><a href="/">Главная</a></li>
+        <li class="active">Мои клубы</li>
+    </ul>
+
+    <div class="page-header animate-fade-in">
+        <h2>🏛 Мои клубы</h2>
+        <p>Заявки и активные участия в приватных клубных витринах.</p>
+    </div>
+
+    @if (memberships is null)
+    {
+        <div class="glass-card" style="padding: 2rem;">
+            <div class="skeleton skeleton-text" style="width: 60%; height: 2rem; margin-bottom: 1rem;"></div>
+            <div class="skeleton skeleton-text" style="width: 80%;"></div>
+        </div>
+    }
+    else if (memberships.Count == 0)
+    {
+        <div class="glass-card public-empty-state">
+            <h2>Вы пока не подавали заявок</h2>
+            <p>Откройте публичную витрину клуба и нажмите «Подать заявку», чтобы стать участником.</p>
+            <a class="btn-gm btn-gm-primary" href="/showcase">К каталогу клубов</a>
+        </div>
+    }
+    else
+    {
+        @if (activeMemberships.Count > 0)
+        {
+            <section class="glass-card animate-slide-up">
+                <h3>Активные участия</h3>
+                <ul class="membership-list">
+                    @foreach (var membership in activeMemberships)
+                    {
+                        <li>
+                            <div class="membership-info">
+                                <a href="@($"/club/{membership.GroupSlug ?? membership.GroupId.ToString()}")" class="membership-name">
+                                    @membership.GroupName
+                                </a>
+                                <span class="status-badge status-success">Участник</span>
+                            </div>
+                            <button type="button" class="btn-gm btn-gm-outline" @onclick="() => Leave(membership.MembershipId)">
+                                Покинуть клуб
+                            </button>
+                        </li>
+                    }
+                </ul>
+            </section>
+        }
+
+        @if (pendingMemberships.Count > 0)
+        {
+            <section class="glass-card animate-slide-up" style="margin-top: 1.5rem;">
+                <h3>Заявки на рассмотрении</h3>
+                <ul class="membership-list">
+                    @foreach (var membership in pendingMemberships)
+                    {
+                        <li>
+                            <div class="membership-info">
+                                <span class="membership-name">@membership.GroupName</span>
+                                <span class="status-badge status-warning">Ожидает одобрения</span>
+                            </div>
+                            <button type="button" class="btn-gm btn-gm-outline" @onclick="() => Leave(membership.MembershipId)">
+                                Отозвать заявку
+                            </button>
+                        </li>
+                    }
+                </ul>
+            </section>
+        }
+
+        @if (historyMemberships.Count > 0)
+        {
+            <section class="glass-card animate-slide-up" style="margin-top: 1.5rem;">
+                <h3>История</h3>
+                <ul class="membership-list">
+                    @foreach (var membership in historyMemberships)
+                    {
+                        <li>
+                            <div class="membership-info">
+                                <span class="membership-name">@membership.GroupName</span>
+                                <span class="status-badge @(membership.Status == "Rejected" ? "status-danger" : "status-neutral")">
+                                    @(membership.Status == "Rejected" ? "Отклонена" : "Вы покинули клуб")
+                                </span>
+                                @if (membership.DecidedAt is not null)
+                                {
+                                    <span class="membership-meta">@membership.DecidedAt.Value.ToString("dd.MM.yyyy")</span>
+                                }
+                            </div>
+                        </li>
+                    }
+                </ul>
+            </section>
+        }
+    }
+
+    @if (!string.IsNullOrEmpty(errorMessage))
+    {
+        <div class="gm-alert gm-alert-danger" style="margin-top: 1rem;">⚠️ @errorMessage</div>
+    }
+</div>
+
+@code {
+    private List<WebMembership>? memberships;
+    private List<WebMembership> activeMemberships = [];
+    private List<WebMembership> pendingMemberships = [];
+    private List<WebMembership> historyMemberships = [];
+    private string? errorMessage;
+
+    protected override async Task OnInitializedAsync()
+    {
+        await LoadAsync();
+    }
+
+    private async Task LoadAsync()
+    {
+        errorMessage = null;
+        memberships = await MembershipService.GetMineAsync();
+        activeMemberships = memberships.Where(m => m.Status == "Active").ToList();
+        pendingMemberships = memberships.Where(m => m.Status == "Pending").ToList();
+        historyMemberships = memberships.Where(m => m.Status is "Rejected" or "Left").ToList();
+    }
+
+    private async Task Leave(Guid membershipId)
+    {
+        errorMessage = null;
+        try
+        {
+            await MembershipService.LeaveClubForCurrentUserAsync(membershipId);
+            await LoadAsync();
+        }
+        catch (InvalidOperationException ex)
+        {
+            errorMessage = ex.Message;
+        }
+    }
+}