Add viewer-range categories, nomination tracking, dynamic showact form, session timeout, share URLs, and workflow-per-season

Features:
- Category viewer ranges + subcategory templates (admin group modal, tree workspace)
- Nomination enrichment via TwitchTracker API (NominationEnrichmentService,
  TwitchTrackerViewerStatsProvider) with admin tracking rules editor
- Nomination group tracker: CategoryGroupName as primary identifier,
  CategoryId stays as nullable legacy field; StreamerIdentity table
- Dynamic showact application form builder (AdminShowactFormBuilder,
  ShowactApplicationSchedule)
- Session idle timeout setting (AdminSessionTimeoutCard)
- Share URLs for X and Discord (SiteSettings, public extras)
- Workflow rules now stored per season (falls back to global SiteSettings)
- New admin routes: settings/access, settings/workflows, tracking-rules
- New admin review workspace with subcategory tabs
- AdminCategoriesView rebuilt with group/subcategory modals

Migrations (all additive):
- AddShareUrls, AddShowactDynamicForm, AddCategoryViewerRanges,
  AddSessionIdleTimeoutSettings, AddSeasonSubcategoryTemplates,
  AddNominationGroupTrackerIdentity, AddShowactApplicationSchedule,
  AddSeasonWorkflowRulesJson

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

Backend/Services/UserSessionService.cs

@@ -1,15 +1,18 @@
 using Backend.Common;
 using Backend.Contracts;
+using Backend.Data;
 using Backend.Domain;
 using Backend.Repositories;
 using Backend.Security;
+using Microsoft.EntityFrameworkCore;
 using System.Security.Cryptography;
 
 namespace Backend.Services;
 
-public sealed class UserSessionService(IUserSessionRepository userSessionRepository) : IUserSessionService
+public sealed class UserSessionService(IUserSessionRepository userSessionRepository, AwardsDbContext db) : IUserSessionService
 {
-    private static readonly TimeSpan IdleSessionLifetime = TimeSpan.FromHours(12);
+    public const int MinimumIdleTimeoutHours = 3;
+    public const int DefaultIdleTimeoutHours = 3;
     private static readonly TimeSpan AbsoluteSessionLifetime = TimeSpan.FromDays(30);
 
     public async Task<UserSession?> ResolveSessionAsync(HttpContext context, CancellationToken cancellationToken = default)
@@ -27,7 +30,8 @@ public sealed class UserSessionService(IUserSessionRepository userSessionReposit
         }
 
         var now = DateTimeOffset.UtcNow;
-        if (IsExpired(session, now))
+        var idleSessionLifetime = await ResolveIdleSessionLifetimeAsync(cancellationToken);
+        if (IsExpired(session, now, idleSessionLifetime))
         {
             session.IsActive = false;
             await userSessionRepository.SaveChangesAsync(cancellationToken);
@@ -40,6 +44,17 @@ public sealed class UserSessionService(IUserSessionRepository userSessionReposit
         return session;
     }
 
+    public async Task<int> GetIdleTimeoutHoursAsync(CancellationToken cancellationToken = default)
+    {
+        var configuredHours = await db.SiteSettings
+            .AsNoTracking()
+            .Where(item => item.Id == 1)
+            .Select(item => (int?)item.SessionIdleTimeoutHours)
+            .FirstOrDefaultAsync(cancellationToken);
+
+        return NormalizeIdleTimeoutHours(configuredHours);
+    }
+
     public Task<UserSession> CreateDevSessionAsync(LoginRequest request, RequestMetadata metadata, CancellationToken cancellationToken = default)
     {
         return CreateSessionAsync(
@@ -94,9 +109,18 @@ public sealed class UserSessionService(IUserSessionRepository userSessionReposit
             : null;
     }
 
-    private static bool IsExpired(UserSession session, DateTimeOffset now) =>
+    private async Task<TimeSpan> ResolveIdleSessionLifetimeAsync(CancellationToken cancellationToken)
+    {
+        var idleTimeoutHours = await GetIdleTimeoutHoursAsync(cancellationToken);
+        return TimeSpan.FromHours(idleTimeoutHours);
+    }
+
+    public static int NormalizeIdleTimeoutHours(int? configuredHours) =>
+        Math.Max(MinimumIdleTimeoutHours, configuredHours ?? DefaultIdleTimeoutHours);
+
+    private static bool IsExpired(UserSession session, DateTimeOffset now, TimeSpan idleSessionLifetime) =>
         session.CreatedAt <= now.Subtract(AbsoluteSessionLifetime)
-        || session.LastSeenAt <= now.Subtract(IdleSessionLifetime);
+        || session.LastSeenAt <= now.Subtract(idleSessionLifetime);
 
     private async Task<UserSession> PersistAndReturnAsync(UserSession session, CancellationToken cancellationToken)
     {