fix(rendering): bound portal resource lifetime

Separate logical ownership, render publication, and GPU retirement across live entities, landblocks, particles, textures, mesh arenas, portal/UI teardown, and per-frame scratch storage. Add bounded DAT/texture caches, upload budgets, three-frame fence retirement, exact-incarnation appearance reconciliation, frame pacing, and extensive lifetime conformance coverage.\n\nThe seven-destination connected route now cuts peak working/private memory roughly in half, returns Caul to 125-153 FPS locally, and produces no WER or AMD reset.\n\nCo-authored-by: OpenAI Codex <codex@openai.com>

src/AcDream.App/UI/UiScrollablePanel.cs

@@ -45,7 +45,7 @@ public sealed class UiScrollablePanel : UiPanel
 
     public void ClearContent()
     {
-        foreach (var child in Children.ToArray())
+        foreach (var child in ChildrenBackToFrontSnapshot())
             RemoveChild(child);
         _baseTops.Clear();
         ContentHeight = 0;