feat(admin): category SEO fields, Templates admin, safe project PATCH

- categories/tags admin forms: add meta title/description/keywords, bot-follow,
  sort, is_active (backend already supported these)
- new Templates admin (/admin/templates): container CRUD with description,
  keywords, publishing, premium, primary mode, category/tag assignment, plus
  editable per-variant aspect & resolution
- content-svc: PATCH /v1/projects/{id} partial update so aspect/resolution edits
  never wipe render/colour data (SharedColorsSvg, RenderAepComp, Folder)
- admin resource proxy: add PATCH passthrough

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

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

@@ -199,6 +199,42 @@ public class TemplateService(ContentDbContext db)
         return await GetProjectDetailAsync(project.Id);
     }
 
+    /// <summary>Partial update — only applies supplied (non-null) fields, so editing an
+    /// aspect/resolution never clears render/colour data the full update would require.</summary>
+    public async Task<ProjectDetailResponse> PatchProjectAsync(Guid id, PatchProjectRequest req)
+    {
+        var project = await db.Projects.FindAsync(id)
+            ?? throw new KeyNotFoundException($"Project {id} not found");
+
+        if (req.Name != null) project.Name = req.Name;
+        if (req.Description != null) project.Description = req.Description;
+        if (req.Aspect != null) project.Aspect = req.Aspect;
+        if (req.Resolution != null)
+        {
+            if (!Enum.TryParse<ResolutionKind>(req.Resolution, true, out var resolution))
+                throw new ArgumentException($"Invalid Resolution: {req.Resolution}");
+            project.Resolution = resolution;
+        }
+        if (req.ChooseMode != null)
+        {
+            if (!Enum.TryParse<ChooseMode>(req.ChooseMode, true, out var chooseMode))
+                throw new ArgumentException($"Invalid ChooseMode: {req.ChooseMode}");
+            project.ChooseMode = chooseMode;
+        }
+        if (req.OriginalWidth.HasValue) project.OriginalWidth = req.OriginalWidth.Value;
+        if (req.OriginalHeight.HasValue) project.OriginalHeight = req.OriginalHeight.Value;
+        if (req.ProjectDurationSec.HasValue) project.ProjectDurationSec = req.ProjectDurationSec.Value;
+        if (req.MinDurationSec.HasValue) project.MinDurationSec = req.MinDurationSec;
+        if (req.MaxDurationSec.HasValue) project.MaxDurationSec = req.MaxDurationSec;
+        if (req.FreeFps.HasValue) project.FreeFps = req.FreeFps.Value;
+        if (req.IsPublished.HasValue) project.IsPublished = req.IsPublished.Value;
+        if (req.Sort.HasValue) project.Sort = req.Sort.Value;
+        project.UpdatedAt = DateTime.UtcNow;
+
+        await db.SaveChangesAsync();
+        return await GetProjectDetailAsync(project.Id);
+    }
+
     public async Task DeleteProjectAsync(Guid id)
     {
         var project = await db.Projects.FindAsync(id)