phase(N.5) Task 6 fixup: log symmetry + Silk extension shortcut

Code quality review caught:
- Silent failure when ARB_bindless_texture absent — the && short-circuit
  meant the most common fallback case (no bindless on the GPU) had no
  log, while ARB_shader_draw_parameters absent did log. Restructured to
  three nested ifs so each failure path logs symmetrically.
- Redundant `bindless is not null` guard removed (TryCreate's non-null
  guarantee covers it; the nested-if structure makes this implicit).
- HasShaderDrawParameters in BindlessSupport.cs replaced its manual
  GL_NUM_EXTENSIONS scan with `gl.IsExtensionPresent(...)` — same
  pattern WB uses, less code.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/AcDream.App/Rendering/Wb/BindlessSupport.cs

@@ -50,13 +50,6 @@ public sealed class BindlessSupport
     /// from this extension.</summary>
     public bool HasShaderDrawParameters(GL gl)
     {
-        int n = 0;
-        gl.GetInteger(GLEnum.NumExtensions, out n);
-        for (int i = 0; i < n; i++)
-        {
-            string ext = gl.GetStringS(StringName.Extensions, (uint)i);
-            if (ext == "GL_ARB_shader_draw_parameters") return true;
-        }
-        return false;
+        return gl.IsExtensionPresent("GL_ARB_shader_draw_parameters");
     }
 }