phase(N.4) Task 17: EntitySpawnAdapter for server-spawned per-instance content

Routes server-spawned (CreateObject) entities through the per-instance
rendering path. Filter: ServerGuid != 0. Atlas-tier entities (procedural,
ServerGuid == 0) flow through LandblockSpawnAdapter (Task 11) instead.

For entities with PaletteOverride set, walks each MeshRef.SurfaceOverrides
map and calls TextureCache.GetOrUploadWithPaletteOverride to pre-warm the
palette-composed GL texture before the first draw. Surfaces not in the
SurfaceOverrides map (i.e. whose ids are only known after opening the GfxObj
dat) are decoded lazily by the draw dispatcher on first use, consistent with
StaticMeshRenderer.

Builds AnimatedEntityState per server-guid via injected sequencer factory
(Func<WorldEntity, AnimationSequencer>). The factory decouples the adapter
from DatCollection so tests pass a stub lambda without a GL context.

OnRemove releases per-entity state. Unknown guids no-op.

Introduces ITextureCachePerInstance: thin seam interface over the palette
decode path so EntitySpawnAdapter tests can use a CapturingTextureCache
mock without constructing a GL context. TextureCache implements it.

Adjustment 4 documented in source comments: WorldEntity does not currently
expose HiddenPartsMask or AnimPartChanges (they are consumed upstream in the
network layer before the WorldEntity is built). HideParts / SetPartOverride
calls are placeholder TODO'd for when those fields are promoted.

Wired into GpuWorldState.AppendLiveEntity (OnCreate) and
RemoveEntityByServerGuid (OnRemove). Constructed in GameWindow under the
ACDREAM_USE_WB_FOUNDATION flag alongside LandblockSpawnAdapter. Sequencer
factory captures _dats + _animLoader at construction time; falls back to an
empty Setup + MotionTable via NullAnimLoader when dats are unavailable.

10 new tests: server-spawn routing, atlas-tier skip, palette decode pre-warm
(with and without surface overrides), OnRemove lifecycle, unknown-guid noop,
multi-entity isolation. All pass; 8 pre-existing failures unchanged.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/AcDream.App/Rendering/TextureCache.cs

@@ -8,7 +8,7 @@ using SurfaceType = DatReaderWriter.Enums.SurfaceType;
 
 namespace AcDream.App.Rendering;
 
-public sealed unsafe class TextureCache : IDisposable
+public sealed unsafe class TextureCache : Wb.ITextureCachePerInstance, IDisposable
 {
     private readonly GL _gl;
     private readonly DatCollection _dats;