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/EditSession.razor

@@ -57,6 +57,16 @@
                     <div class="gm-form-hint">Пустое значение означает запись без лимита. Если лимит заполнен, новые игроки попадут в лист ожидания.</div>
                 </div>
 
+                <div class="gm-form-group">
+                    <label class="gm-form-label">Режим публикации</label>
+                    <InputSelect @bind-Value="model.PublicationMode" class="gm-form-control">
+                        <option value="@PublicationModeExtensions.NoneValue">Скрыта</option>
+                        <option value="@PublicationModeExtensions.CatalogValue">В каталоге</option>
+                        <option value="@PublicationModeExtensions.ClubOnlyValue">Только для участников клуба</option>
+                        <option value="@PublicationModeExtensions.BothValue">Каталог + клуб</option>
+                    </InputSelect>
+                </div>
+
                 <div style="display: flex; gap: 0.75rem; margin-top: 1.5rem;">
                     <button type="submit" class="btn-gm btn-gm-success" disabled="@isSubmitting">
                         @(isSubmitting ? "⏳ Сохранение..." : "✅ Сохранить изменения")
@@ -104,6 +114,7 @@
         model.ScheduledAtLocal = session.ScheduledAt.ToMoscow();
         model.JoinLink = session.JoinLink;
         model.MaxPlayers = session.MaxPlayers;
+        model.PublicationMode = session.PublicationMode;
     }
 
     private async Task HandleSubmit()
@@ -123,6 +134,7 @@
             var utcTime = new DateTimeOffset(model.ScheduledAtLocal, TimeSpan.FromHours(3)).ToUniversalTime().UtcDateTime;
 
             await SessionService.UpdateSessionForCurrentUserAsync(SessionId, model.Title, utcTime, model.JoinLink, model.MaxPlayers);
+            await SessionService.SetSessionPublicationModeForCurrentUserAsync(SessionId, PublicationModeExtensions.FromDatabaseValue(model.PublicationMode));
             Navigation.NavigateTo($"/group/{session!.GroupId}");
         }
         catch (SessionAccessDeniedException)
@@ -147,5 +159,6 @@
         public DateTime ScheduledAtLocal { get; set; } = DateTime.Now;
         public string JoinLink { get; set; } = "";
         public int? MaxPlayers { get; set; }
+        public string PublicationMode { get; set; } = PublicationModeExtensions.NoneValue;
     }
 }