fix #426: extract solid-colour (NO_POS_UVS) faces; skip untextured subsets only on building shells and cells like retail

The Holtburg windmill axle (GfxObj 0x010010CE, 8 polygons, all
Stippling.NoPos + SurfaceType.Base1Solid) extracted to a 0-vertex mesh.
NoPos ("NO_POS_UVS", acclient.h:7380-7388) means "this side has no
texture coordinates" — true of every solid-colour polygon, since
nothing samples them — not "there is no positive face". Extraction read
it as the latter and dropped the polygon entirely, client-wide, for
every untextured polygon on every object.

Retail's D3DPolyRender::DrawMesh (@0x0059d4a0, named-retail decomp
~line 426048) draws an untextured subset on an ordinary object exactly
like a textured one; the only retail cases that skip an untextured
subset are a building shell (RenderDeviceD3D::DrawBuilding @0x0059f2a0
sets ObjBuildingOrBuildingPart=1) or an EnvCell interior
(RenderDeviceD3D::DrawEnvCell @0x0059f170, arg4=1). The #119
investigation's "retail's skipNoTexture never draws them either"
conclusion was itself wrong as a general rule.

- MeshExtractor.PrepareGfxObjMeshData / GfxObjMesh.Build: emit the
  positive side whenever PosSurface is a valid index, regardless of
  NoPos; the existing UV-index-0 fallback already produces zero
  texcoords for a NoPos polygon with no UVs on the wire.
- RetailUntexturedSurfacePolicy.IsUntextured(SurfaceType): the one
  place that answers "is this surface textured"
  ((type & (Base1Image|Base1ClipMap)) == 0), replacing the old
  `isSolid = NoPos || Base1Solid` (which also mis-classified a NEG-side
  batch by the POS-side's NoPos flag).
- RetailUntexturedSubsetPolicy.Draws(isBuildingShell, isUntextured):
  the shared draw-time gate wired into WbDrawDispatcher.ClassifyBatches,
  .PackedOracle.ClassifyPackedBatches, and
  .DirectionalShadows.AddDirectionalShadowBatches — one predicate so the
  three walks cannot drift (Campaign VM VM6 lesson).
- CellMesh.cs / MeshExtractor.PrepareCellStructMeshData deliberately
  KEEP their NoPos-gated skip for cell-wall geometry — retail's
  DrawEnvCell really does skip untextured subsets there; register row
  AP-234 documents the NoPos-vs-Surface.Type approximation.
- PakFormat.CurrentBakeToolVersion 4->5 (LauncherInstallRecordStore in
  lockstep): a pak baked by an older tool is missing every untextured
  face. No bake was run as part of this commit.

Also fixed: WorldBuilder's own upstream ObjectMeshManager.cs has the
identical NoPos bug (ObjectMeshManager.cs:959,984) — our port had
faithfully carried it over, and our own conformance test
(Build_NoPosFlag_OnlyEmitsNegSide) asserted the bug as correct WB
conformance. Renamed/reworded to Build_NoPosFlag_EmitsBothPosAndNegSide
with a citation for why retail decomp overrides WB here.

Issue119UpNullGfxObjDumpTests re-run against the installed DAT:
#119's own two objects (0x010002B4 9/9 polys, 0x010008A8 1/1 poly) now
gate DRAWS on every polygon instead of extracting to nothing.

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

tests/AcDream.Launcher.Core.Tests/Installation/LauncherInstallerTests.cs

@@ -51,12 +51,12 @@ public sealed class LauncherInstallerTests : IDisposable
             await File.WriteAllTextAsync(request.OutputPath, "complete prepared package");
             long bytes = new FileInfo(request.OutputPath).Length;
             output("acdream-bake human header\n{\"v\":1,\"e\":\"star");
-            output("ted\",\"bakeToolVersion\":4,\"outputPath\":\"pak\"}\n");
+            output($"ted\",\"bakeToolVersion\":{LauncherInstallRecordStore.CurrentBakeToolVersion},\"outputPath\":\"pak\"}}\n");
             output("{\"v\":1,\"e\":\"progress\",\"phase\":\"mesh\","
                 + "\"completed\":25,\"total\":100,\"failures\":0,"
                 + "\"elapsedSeconds\":5,\"etaSeconds\":15}\n");
             output("{\"v\":1,\"e\":\"newMetric\",\"value\":1}\n");
-            output($"{{\"v\":1,\"e\":\"completed\",\"bakeToolVersion\":4,"
+            output($"{{\"v\":1,\"e\":\"completed\",\"bakeToolVersion\":{LauncherInstallRecordStore.CurrentBakeToolVersion},"
                 + $"\"outputBytes\":{bytes},\"failures\":0}}\n");
             return new BakeProcessResult(0, string.Empty);
         });
@@ -153,7 +153,7 @@ public sealed class LauncherInstallerTests : IDisposable
                 async (request, output, _) =>
                 {
                     await File.WriteAllTextAsync(request.OutputPath, "partial replacement");
-                    output("{\"v\":1,\"e\":\"started\",\"bakeToolVersion\":4}\n");
+                    output($"{{\"v\":1,\"e\":\"started\",\"bakeToolVersion\":{LauncherInstallRecordStore.CurrentBakeToolVersion}}}\n");
                     output("{\"v\":1,\"e\":\"error\",\"message\":\"fixture failed\"}\n");
                     return new BakeProcessResult(9, "human failure detail");
                 },
@@ -186,9 +186,9 @@ public sealed class LauncherInstallerTests : IDisposable
                 {
                     await File.WriteAllTextAsync(request.OutputPath, "contradictory output");
                     long bytes = new FileInfo(request.OutputPath).Length;
-                    output("{\"v\":1,\"e\":\"started\",\"bakeToolVersion\":4}\n");
+                    output($"{{\"v\":1,\"e\":\"started\",\"bakeToolVersion\":{LauncherInstallRecordStore.CurrentBakeToolVersion}}}\n");
                     output("{\"v\":1,\"e\":\"error\",\"message\":\"first failure\"}\n");
-                    output($"{{\"v\":1,\"e\":\"completed\",\"bakeToolVersion\":4,"
+                    output($"{{\"v\":1,\"e\":\"completed\",\"bakeToolVersion\":{LauncherInstallRecordStore.CurrentBakeToolVersion},"
                         + $"\"outputBytes\":{bytes},\"failures\":0}}\n");
                     return new BakeProcessResult(0, string.Empty);
                 });
@@ -275,8 +275,8 @@ public sealed class LauncherInstallerTests : IDisposable
             Directory.CreateDirectory(Path.GetDirectoryName(request.OutputPath)!);
             await File.WriteAllTextAsync(request.OutputPath, "complete but unverified");
             long bytes = new FileInfo(request.OutputPath).Length;
-            output("{\"v\":1,\"e\":\"started\",\"bakeToolVersion\":4}\n");
-            output($"{{\"v\":1,\"e\":\"completed\",\"bakeToolVersion\":4,"
+            output($"{{\"v\":1,\"e\":\"started\",\"bakeToolVersion\":{LauncherInstallRecordStore.CurrentBakeToolVersion}}}\n");
+            output($"{{\"v\":1,\"e\":\"completed\",\"bakeToolVersion\":{LauncherInstallRecordStore.CurrentBakeToolVersion},"
                 + $"\"outputBytes\":{bytes},\"failures\":0}}\n");
             return new BakeProcessResult(0, string.Empty);
         });