Revert "Campaign V slice V4a" - it lost world multisampling

This reverts ceec3bc4. Two independent reasons, either sufficient.

The rendering regression. The slice deleted TextRenderGlStateScope, which
saved GL_MULTISAMPLE and GL_SAMPLE_ALPHA_TO_COVERAGE on entry, disabled them
for the text pass, and restored them on exit (TextRenderGlStateScope.cs:111-112
and 153-154 at the parent commit). Its replacement bakes that state into the
text pipeline but nothing restores it, and GlGpuPassEncoder.Dispose does not
either. Every world renderer is still raw GL at this point in the campaign, so
from the first UI frame onward the world drew with multisampling disabled.

The offline pixel gate caught it: 1,791 of 563,200 compared pixels differed,
0.318% against a 0.001 threshold. The commit message attributed this to
wall-clock-driven ambient animation shifting phase, and committed through the
failure. That explanation does not survive its own control: capturing twice at
the reverted-to commit differs by 19 pixels and twice at the slice's own commit
by 8, while base-versus-head differs by 1,791 - a 224x gap that no shared-noise
source explains. An amplified difference image settles it visually: the changed
pixels are the silhouette edges of every tree, building and rock, with terrain
interiors, water and the entire UI untouched. That is the signature of losing
edge antialiasing, not of animated sprites.

This is the exact failure mode two existing memory notes already warn about -
a mid-frame renderer must set every GL state it uses rather than inherit it,
and issue #52's lesson that a rendering migration must audit per-pass GL state
before declaring itself done.

The scope. The brief was three small leaf renderers plus additive frame-
lifecycle wiring, roughly ten files. The commit changed 334 files with 3,665
insertions and 3,845 deletions, including 323 public-to-internal visibility
conversions across the App assembly, 55 test files, two retired conformance
tests, and a self-described temporary escape hatch for bridging raw-GL viewport
textures. Even without the regression, that is not separable into the part
worth keeping and the part worth dropping.

Reverting rather than patching because the good work here - the RHI frame
lifecycle wiring and a genuine render-state-cache staleness fix - is small
enough to redo cleanly against a tightened spec, while untangling it from 300+
files of unrelated churn is not.

Post-revert: Release build clean, App suite back to 3,843 passed / 3 skipped,
offline pixel gate passing at 19 differing pixels.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/AcDream.App/Rendering/ClipFrame.cs

@@ -1,20 +1,20 @@
-// ClipFrame.cs
+// ClipFrame.cs
 //
 // Phase U.3: the GPU-side container + uploader for the SHARED per-frame clip
 // data consumed by mesh_modern.vert (SSBO binding=2) and terrain_modern.vert
 // (UBO binding=2). This is the "shared" half of the U.3 clip mechanism; the
 // per-instance slot index buffer (SSBO binding=3) is PER-RENDERER and owned by
 // each renderer (WbDrawDispatcher / EnvCellRenderer), parallel to its instance
-// buffer — it is NOT here.
+// buffer — it is NOT here.
 //
 // === The contract (both shader sides obey) ===================================
 // binding=2 mesh SSBO holds an array of CellClip, one per "slot":
 //     struct CellClip { uint count; uint _p0; uint _p1; uint _p2; vec4 planes[8]; };
 //   std430 layout: count at byte 0, three pad uints at 4/8/12, planes[8] at 16
-//   (vec4 stride 16) → 144 bytes per slot. Slot 0 is RESERVED = no-clip (count 0).
+//   (vec4 stride 16) → 144 bytes per slot. Slot 0 is RESERVED = no-clip (count 0).
 // binding=2 terrain UBO holds the single OutsideView region:
 //     layout(std140) { int uTerrainClipCount; vec4 uTerrainClipPlanes[8]; };
-//   std140 layout: count at byte 0 (padded to 16), planes[8] at 16 → 144 bytes.
+//   std140 layout: count at byte 0 (padded to 16), planes[8] at 16 → 144 bytes.
 //
 // In U.3 a ClipFrame is built via NoClip(): one slot (slot 0, count 0) and a
 // terrain count of 0. Everything renders exactly as before. U.4 populates real
@@ -40,16 +40,16 @@ namespace AcDream.App.Rendering;
 /// std430 / std140 byte layout. Per-instance slot buffers (binding=3) are owned by
 /// each renderer, not here.
 /// </summary>
-internal sealed class ClipFrame : IDisposable
+public sealed class ClipFrame : IDisposable
 {
     // ---- Layout constants (mirror mesh_modern.vert + terrain_modern.vert) ----
 
-    /// <summary>Max planes per clip region — matches the shader's <c>planes[8]</c>
+    /// <summary>Max planes per clip region — matches the shader's <c>planes[8]</c>
     /// and GL's guaranteed <c>GL_MAX_CLIP_DISTANCES &gt;= 8</c>.</summary>
     public const int MaxPlanes = 8;
 
     /// <summary>std430 stride of one <c>CellClip</c>: 16 (count + 3 pad uints) +
-    /// 8 × 16 (vec4 planes) = 144 bytes.</summary>
+    /// 8 × 16 (vec4 planes) = 144 bytes.</summary>
     public const int CellClipStrideBytes = 16 + MaxPlanes * 16; // 144
 
     /// <summary>Byte offset of <c>planes[0]</c> within a <c>CellClip</c> (after the
@@ -57,7 +57,7 @@ internal sealed class ClipFrame : IDisposable
     public const int CellClipPlanesOffset = 16;
 
     /// <summary>std140 size of the terrain UBO block: int count padded to 16, then
-    /// 8 × 16 (vec4 planes) = 144 bytes. Same number as the SSBO stride by
+    /// 8 × 16 (vec4 planes) = 144 bytes. Same number as the SSBO stride by
     /// coincidence of the 16-byte vec4 rule, but a DIFFERENT layout family.</summary>
     public const int TerrainUboBytes = 16 + MaxPlanes * 16; // 144
 
@@ -66,7 +66,7 @@ internal sealed class ClipFrame : IDisposable
     public const uint MeshClipSsboBinding = 2;
 
     /// <summary>UBO binding index for the terrain OutsideView clip region
-    /// (terrain_modern.vert binding=2). UBO namespace — distinct from the SSBO
+    /// (terrain_modern.vert binding=2). UBO namespace — distinct from the SSBO
     /// binding=2 above.</summary>
     public const uint TerrainClipUboBinding = 2;
 
@@ -139,23 +139,23 @@ internal sealed class ClipFrame : IDisposable
 
     /// <summary>
     /// The U.3 default frame: exactly slot 0 (no-clip, count 0) and a terrain
-    /// count of 0. The whole scene renders ungated — identical to pre-U.3. U.4
+    /// count of 0. The whole scene renders ungated — identical to pre-U.3. U.4
     /// replaces this with a frame built from real portal visibility.
     /// </summary>
     public static ClipFrame NoClip()
     {
-        // One slot, all zeros: count=0 ⇒ shader passes every plane.
+        // One slot, all zeros: count=0 ⇒ shader passes every plane.
         var bytes = new byte[CellClipStrideBytes];
         return new ClipFrame(bytes, slotCount: 1);
     }
 
-    /// <summary>Number of clip slots currently packed (always &gt;= 1 — slot 0 is
+    /// <summary>Number of clip slots currently packed (always &gt;= 1 — slot 0 is
     /// the reserved no-clip slot).</summary>
     public int SlotCount => _slotCount;
 
     /// <summary>
-    /// Phase U.4: reset this frame back to the NoClip state — exactly slot 0
-    /// (no-clip, count 0) and a terrain count of 0 — WITHOUT allocating a new
+    /// Phase U.4: reset this frame back to the NoClip state — exactly slot 0
+    /// (no-clip, count 0) and a terrain count of 0 — WITHOUT allocating a new
     /// frame or new GL buffers. The single long-lived <c>_clipFrame</c> in
     /// GameWindow is reset + re-packed every frame by <see cref="ClipFrameAssembler"/>,
     /// then uploaded through one SSBO and one terrain arena per fenced frame slot.
@@ -209,7 +209,7 @@ internal sealed class ClipFrame : IDisposable
     /// <summary>
     /// Append one clip region (becomes the next slot index) from a
     /// <see cref="ClipPlaneSet"/>. Only the convex-plane case is supported in
-    /// U.3 — <c>Count &gt; 0</c> packs that many planes; <c>Count == 0</c> packs a
+    /// U.3 — <c>Count &gt; 0</c> packs that many planes; <c>Count == 0</c> packs a
     /// no-clip region (pass-all). The scissor / nothing-visible fallbacks that
     /// <see cref="ClipPlaneSet"/> can carry are deferred to U.4 (which will draw
     /// the AABB box or skip the cell on the CPU side, not via this slot). Returns
@@ -259,7 +259,7 @@ internal sealed class ClipFrame : IDisposable
     /// <summary>
     /// Set the terrain OutsideView clip region (the single region the terrain
     /// shader gates against). <paramref name="planes"/> length 0 ungates terrain
-    /// (count 0). U.3 callers never touch this — <see cref="NoClip"/> leaves it
+    /// (count 0). U.3 callers never touch this — <see cref="NoClip"/> leaves it
     /// at count 0. U.4 calls it with the OutsideView planes.
     /// </summary>
     public void SetTerrainClip(ReadOnlySpan<Vector4> planes)
@@ -579,7 +579,7 @@ internal sealed class ClipFrame : IDisposable
 }
 
 /// <summary>A single std140 terrain-clip record within a frame-slot UBO arena.</summary>
-internal readonly record struct TerrainClipBufferBinding(
+public readonly record struct TerrainClipBufferBinding(
     uint Buffer,
     int OffsetBytes,
     int SizeBytes)