feat(content+admin): content ranking + statistics dashboard

- content-svc: template list gains popularity/rating sort modes (use_count_desc,
  popular, rating_desc); new PATCH /v1/templates/{id}/sort to set manual sort
  weight (feature/pin) without a full edit
- admin /admin/ranking: templates ordered by popularity with views/uses/rating
  and inline manual-sort editor
- admin /admin/stats: overview dashboard (users, revenue, paying customers,
  conversion, templates/categories/campaigns/blogs counts) aggregated from
  existing identity + content endpoints
- nav: Dashboard + Ranking links

Completes the epic: SMS/Email/Templates → Marketing → CRM → Ranking + Stats.

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

services/content/FlatRender.ContentSvc/Application/Services/TemplateService.cs

@@ -43,6 +43,8 @@ public class TemplateService(ContentDbContext db)
             "sort_asc" => q.OrderBy(x => x.Sort),
             "name_asc" => q.OrderBy(x => x.Name),
             "view_count_desc" => q.OrderByDescending(x => x.ViewCount),
+            "use_count_desc" or "popular" => q.OrderByDescending(x => x.UseCount).ThenByDescending(x => x.ViewCount),
+            "rating_desc" => q.OrderByDescending(x => x.RateAvg).ThenByDescending(x => x.RateCount),
             _ => q.OrderByDescending(x => x.SortDate)
         };
 
@@ -132,6 +134,16 @@ public class TemplateService(ContentDbContext db)
         await db.SaveChangesAsync();
     }
 
+    /// <summary>Lightweight ranking update — set a template's manual sort weight without a full edit.</summary>
+    public async Task SetContainerSortAsync(Guid id, int sort)
+    {
+        var container = await db.ProjectContainers.FindAsync(id)
+            ?? throw new KeyNotFoundException($"Container {id} not found");
+        container.Sort = sort;
+        container.UpdatedAt = DateTime.UtcNow;
+        await db.SaveChangesAsync();
+    }
+
     public async Task<ProjectDetailResponse> GetProjectDetailAsync(Guid id)
     {
         var project = await db.Projects