Carry flat, square and round outline caps through ShapeExtra, DrawingML and VML
import, DOCX export, display items, raster strokes and PDF strokes. Keep older
JSON documents default-flat and preserve WordCraft ink's tool-defined caps.
Add JSON, DOCX/VML round-trip, raster-pixel and PDF-operator regressions. Record
the verified coverage and remaining theme/native Word checks in the parity docs.
Co-Authored-By: GPT-6 <codex@openai.com>