Native annotation fill controls (#4406)

The bounded first geometry slice processes direct IfcAnnotationFillArea items on actual IfcAnnotation products. Accepted non-body representation types are Annotation2D and Surface2D. Existing body representations continue through the same router. No primitive is registered globally, so a building type's auxiliary footprint map remains absent from its body geometry.

The initial boundary subset is explicitly closed IfcPolyline rings of finite 2D/3D Cartesian points. At most 64 rings and 2,048 input vertices per fill are accepted. Nonplanar, touching, crossing, open, outside or nested-hole boundaries are refused before triangulation (planarity uses a relative tolerance of 1e-10 times the largest boundary extent). The existing canonical triangulator produces the triangles; existing router scaling and placement produce world coordinates. Indexed/curved boundaries and text are outside this slice. Mixed RGB+hatch/tile paint, invalid/out-of-range RGB and exhausted style-reference budgets explicitly refuse the fill with a diagnostic. Source-bound inverse lookups are shared by the existing columnar entity index across native jobs and WASM batches. This is ordinary IFC processing support, not PDF-to-annotation conversion.

oracle.json records independent IfcOpenShell 0.8.2 geometry for the explicit millimetre control in rust/processing/tests/annotation_fills_4406.rs. Both horizontal and vertical fills have an outer four-metre square and a one-metre square hole. Schema validation reports no errors (all EXPRESS rules were not run). The independent reader confirms area, bounds and triangle count. Its geometry API emits a default material for this fill style; this evidence does not claim cross-reader rendered-colour parity. Native tests assert colour against the authored IfcFillAreaStyle → IfcColourRgb leaf and check its IFC2x3 presentation-assignment wrapper separately.

The fixture is a stated geometric control, not a captured real building or an accuracy measurement. No source IFC assets are committed. The oracle retains its shape owner while reading geometry; releasing a temporary IfcOpenShell shape before accessing its borrowed geometry invalidates that data.

Validation and performance

Native controls exercise both ring windings, triangle/normal agreement, invalid boundaries, mixed/invalid paint, source-index reuse and duplicate-ID refusal. Actual WASM prepass/batch controls preserve geometry/colour and refuse invalid paint. Full Rust and WASM contract suites, strict workspace clippy, root Turbo typechecking and a fresh PyO3 wheel's committed-reference parity quick lane pass.

native-load.json records two interleaved base/branch pairs with five native iterations per run on AC20, using separately built immutable binaries. Paired reported best-of-five phase timings, mesh census and the separately checked mesh fingerprints match. This is ordinary load regression evidence; it does not measure annotation throughput or browser worker-pool performance. The annotation control's expected new meshes are validated separately from the unchanged building fixture.