Restore authored DMO placements and correct grime UV scaling; revert hair changes

docs/dynamic-props-and-grime.md

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+# Authored props and grime follow-up
+
+## Hair rollback
+
+Removed the hair-specific changes from 96adff5 at the user's request: coverage
+texture bindings/blending, depth coverage, exported secondary UVs, FLOAT2 vendor
+decoder correction and its test. The private character package was regenerated
+with the previous exporter. Character probe smoothing remains. The other
+worktree's hair implementation was not touched or imported.
+
+## Grime coordinates
+
+The map writer flips both texture rows and base UV V. The world shader formerly
+sampled macro/detail maps at `flippedUV * scale`. For a scale of 0.3 this gives
+`0.3 - 0.3*v`, but the matching texture-row coordinate is `1 - 0.3*v`: a 0.7
+texture-period displacement. MegaPark's authored macro scale is approximately
+0.3. This shifts stains onto different parts of the ramps and over decal paint.
+
+Macro and detail UVs now scale in the original coordinate system, then flip V.
+The authored opacity and native-reference overlay equation are unchanged:
+`saturate((macro.rgb - 0.5) * opacity + 0.5)`, multiplied over the linear
+diffuse/decal composite. Reference: scene.hlsl in native renderer commit
+f6e0ae87fdfecbadb5c1e36c55d66a744187a3cd. No arbitrary global grime reduction
+was introduced. Perceived strength still requires an in-game comparison after
+the coordinate correction; adaptive exposure also changes overall brightness.
+
+## Dynamic-object initial placement
+
+Observed source: district Sim RX2 `0xEB001D` records have a 32-byte header,
+128-byte records, row-vector affine matrix at +0, world bounds at +64,
+instance/locator IDs at +96/+104, template ID at +112 and name offset at +124.
+Native TU3 `0x825876D0` (community symbol SimManager::SpawnStatic) loads the
+translation at +48 and template ID at +112 before the DMO model lookup.
+Mapped image SHA256:
+F4AA113EB541BFBA03DBC108CF5AB43F58C965B20FA3B82F9C40938A0AD841C4.
+
+`worlddmo.big` supplies reusable templates. Their EB000D 160-byte tInstance
+records bind template IDs to EB0001 model sections. Model mesh tables reference
+EB0023 sections, which reference the vertex declarations. The exporter follows
+those indices, never mesh order or material display names. Material texture
+GUIDs come from the binary channel bindings: the DMO texture namespace's high
+bit is absent from display-name suffixes, so suffix matching loses textures.
+
+The exporter composes model, template and locator matrices in row-vector order;
+normals use the inverse transpose. Reflections reverse triangle winding. It
+neither snaps objects to terrain nor changes their authored matrices. Structured
+JSON alongside each presentation package retains IDs, matrices, source hashes,
+offsets and unresolved locators for a future dynamic runtime.
+
+Offline restored placements:
+
+| Map | Placed | Unresolved |
+| --- | ---: | ---: |
+| University | 479 | 0 |
+| DownTown | 786 | 14 |
+| Industrial | 162 | 18 |
+| BlackBoxPark | 12 | 0 |
+| MaloofMoneyCup | 31 | 0 |
+| Remaining five maps | 0 | 0 |
+
+All University placements resolve. 478 of 479 transformed render bounds agree
+with their authored locator bounds within 5 cm (most within millimetres). One
+open dumpster differs by about 14.5 cm; its authored matrix is retained, since
+render bounds and assembly/animated bounds need not coincide.
+
+The 32 unresolved Downtown/Industrial locators reference six template IDs absent
+from the supplied DMO catalog. The named assets are also absent from parkassets
+by those IDs, and district presentation template tables do not define them.
+They remain explicit unresolved records; no substitute geometry is invented.
+
+Runtime loads private/native-props presentation supplements alongside the
+existing backdrop packages. This restores visible initial placement only:
+objects are not yet pushable, droppable or collidable. Their current materials
+use the existing PBR fallback, not the native dynamicobject lighting shader.
+No static district collision, gameplay or animation logic was changed.
+
+Validation: synthetic record, rotation/scale/normal and invalid-reference tests;
+original-data template resolution and placement-bound comparison; offline map
+readers and shader composition. Game/recomp was not launched. GPU execution,
+appearance, performance and gameplay interaction are not validated here.