feat(ugc): processing totals on the UGC page; no shared icon preset for player models

- IUgc::GetUgcProcessTotals sums what the UGC server made, for models and
  for car and rocket builds: count, time spent (and how many are timed),
  CPU time, average and slowest, average and most memory (estimate),
  bricks, triangles and triangles saved (models whose count before hidden
  face removal is known). /api/ugc returns them as totals and the UGC page
  shows a card for each kind. Parity tested.
- Player models no longer have a shared icon preset: every one is a
  different size and shape, so its icon is fitted to it from the settings.
  The UGC server ignores a kind:model preset, the dashboard refuses to save
  one, and the icon editor hides the type buttons for models. One model's
  own icon values still work. Car and rocket build types keep theirs.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

dDashboardServer/templates/ugc.jinja2

@@ -23,8 +23,9 @@
 	<details class="card mb-3" id="presetsCard">
 		<summary class="card-header py-2 small fw-semibold">Icon presets per type</summary>
 		<div class="card-body py-2 small">
-			<p class="text-body-secondary mb-2">Each type of icon (player models, and each car or rocket build type in the client's data) has a preset over the
-				default settings. Open one to set its camera, the model's turn, the light and the border on an example.</p>
+			<p class="text-body-secondary mb-2">Each car or rocket build type in the client's data has a preset over the default settings. Open one to set
+				its camera, the model's turn, the light and the border on an example. Player models have no preset: each one is a different size and
+				shape, so its icon is fitted to it from the defaults; open a model to change just its icon.</p>
 			<div class="d-flex flex-wrap gap-2" id="presetsList">Loading…</div>
 			<div data-ugc-settings="UGC icons" data-title="Icon defaults (under every preset)"></div>
 		</div>