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/Endpoints/AdminSeasonCreateEndpoints.cs

@@ -28,6 +28,10 @@ public static partial class AdminSeasonManagementEndpoints
         }
 
         var showStreamUrl = NormalizeSeasonStreamUrl(request.ShowStreamUrl);
+        var settings = await db.SiteSettings
+            .AsNoTracking()
+            .FirstOrDefaultAsync(item => item.Id == 1, context.RequestAborted);
+        var initialWorkflowRulesJson = WorkflowRuleSettings.Serialize(WorkflowRuleSettings.Read(settings));
 
         var season = new Season
         {
@@ -45,6 +49,8 @@ public static partial class AdminSeasonManagementEndpoints
             ReviewEndsAt = request.ReviewEndsAt,
             ShowDate = request.ShowDate,
             ShowStartsAt = request.ShowStartsAt,
+            SubcategoryTemplatesJson = "[]",
+            WorkflowRulesJson = initialWorkflowRulesJson,
         };
 
         db.Seasons.Add(season);
@@ -72,6 +78,13 @@ public static partial class AdminSeasonManagementEndpoints
                 .ToArrayAsync(context.RequestAborted);
 
             copiedCategoryCount = sourceCategories.Length;
+            var sourceSeason = await db.Seasons
+                .AsNoTracking()
+                .FirstAsync(item => item.Id == sourceSeasonId, context.RequestAborted);
+            season.SubcategoryTemplatesJson = sourceSeason.SubcategoryTemplatesJson;
+            season.WorkflowRulesJson = string.IsNullOrWhiteSpace(sourceSeason.WorkflowRulesJson)
+                ? initialWorkflowRulesJson
+                : sourceSeason.WorkflowRulesJson;
             foreach (var category in sourceCategories)
             {
                 db.Categories.Add(new Category
@@ -83,6 +96,8 @@ public static partial class AdminSeasonManagementEndpoints
                     Description = category.Description,
                     SortOrder = category.SortOrder,
                     MaxNomineesPerUser = category.MaxNomineesPerUser,
+                    ViewerRangeMin = category.ViewerRangeMin,
+                    ViewerRangeMax = category.ViewerRangeMax,
                 });
             }
         }