Epic: Paint Tools

[fernandotonon]

Goal

Add painting workflows to QtMeshEditor (ZBrush-inspired), starting with a practical MVP and expanding to texture painting + baking.

Non-goals (for this epic)

• Full ZBrush-style sculpting / dynamesh / subdivision pipeline.

Proposed roadmap

• Vertex Color Paint MVP (polypaint-style)
• Texture Paint MVP (paint into BaseColor texture)
• Bake Vertex→Texture, UV seam dilation, multi-material support

Tracking checklist

• Paint: Vertex Color painting tool (MVP) #314 — Vertex Color painting tool (MVP)
• Paint: Vertex Paint UI in Inspector (QML) #315 — Vertex Paint UI in Inspector (QML)
• Paint: Undo/Redo for paint strokes #316 — Undo/Redo for paint strokes
• Paint: Texture painting MVP (BaseColor) #317 — Texture painting MVP (BaseColor)
• Paint: Texture paint resource I/O (load/save, dirty rect updates) #318 — Texture paint resource I/O (load/save, dirty rect updates)
• Paint: Bake vertex colors to texture (with seam padding) #319 — Bake vertex colors to texture (with seam padding)
• Export: Preserve vertex colors in formats that support it #320 — Preserve vertex colors in export
• Docs: Painting tools usage + workflow #321 — Docs

Notes

• Integrate with UndoManager.
• UI should be QML (PropertiesPanel) consistent with current architecture.