feat(rendering): port retail one-pass detail material

Replace the building and EnvCell detail replay with retail's exact single-pass stage result, including authored surface opacity, squared detail alpha, final-alpha clipping, and the original subset pipeline/order. Arm the ordered walk command in place to close #471, delete the replay pipelines/shaders, and advance prepared content to recipe 9.

Mutation witnesses (each restored before commit):
- X=a*qA: RetailDetailTextureContractTests.BothShaderFamiliesUseTheSharedOnePassSourceAndDebugPrecedesDetailSample line 174, missing materialAlpha * detail.a * detail.a.
- X*=base alpha: same test line 175, forbidden baseTexel.a found.
- CLIP against base alpha: EnvCellAlphaDrawSourceTests.ClipShaders_UseGreaterEqualForThePerRangeReference line 260, final-X conditional missing.
- second detail draw: EnvCellAlphaDrawSourceTests.DetailOn_EveryEnvCellFamilyDrawsOnceInPlaceWithAuthoredOpacity line 105, Assert.Single saw 2 MDI calls.
- straight-alpha substitution: WalkStaticStreamPopulatorTests.ImmediateBuildingDetail_RetainsOriginalFramebufferFamily line 1244, Additive first failed (only wb-mesh-alpha-1x recorded; InvAlpha also failed).
- omit ordered arm: OrderPreservingSubmitterTests.PrepareThenDraw_OrdinaryBuildingClipBuildingOrdinary_ArmsOnePassInPlace line 305, expected (77,3.5), got (0,0).
- omit atmospheric combine: RetailDetailTextureContractTests.BothShaderFamiliesUseTheSharedOnePassSourceAndDebugPrecedesDetailSample line 173, atmospheric shared include missing.
- drop serialized opacity: ObjectMeshDataSerializerTests.SurfaceOpacity_RoundTripsBitExactlyAndDeterministically line 288, first reported 0.5 bits 1056964608 vs 1065353216.
- stale detail arm: ordered adjacency test line 307, expected following ordinary (0,0), got (77,3.5).
- per-frame surface map: EnvCellAlphaDrawSourceTests.ProductionWholeLeaf_WarmedScanSubmitRhiAndFilteredReplayDoNotAllocate line 178, expected 0 B, got 147456 B.

Verification before commit: shader compiler 23/23; focused App 213/213; Content 75/75; Core Wb 10/10; launcher migration 6/6; Release solution build 0 warnings / 0 errors; git diff --check clean.

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

@@ -6,13 +6,13 @@ namespace AcDream.App.Rendering.Wb {
     /// Consists of a texture-table slot (Campaign V slice V2; was a raw 64-bit
     /// bindless handle) and the layer index within the shared/pooled array.
     /// Indexed by gl_DrawIDARB in the vertex shader. Same 16-byte std430 shape
-    /// as mesh_modern.vert's BatchData: TextureTableIndex/Reserved/TextureIndex/
+    /// as mesh_modern.vert's BatchData: TextureTableIndex/SurfaceOpacity/TextureIndex/
     /// Flags at offsets 0/4/8/12 — see ModernBatchDataLayoutTests.
     /// </summary>
     [StructLayout(LayoutKind.Sequential, Pack = 4)]
     public struct ModernBatchData {
         public uint TextureTableIndex; // 4 bytes — slot into the binding=9 handle table
-        public uint Reserved;          // 4 bytes — pad, keeps TextureIndex/Flags at offsets 8/12
+        public float SurfaceOpacity;   // 4 bytes — authored material alpha
         public uint TextureIndex;      // 4 bytes — layer within the texture array
         public uint Flags;             // 4 bytes — reserved, matches mesh_modern.vert's BatchData.flags
     }