v4.0-Pre-Alpha

Scene objects previously rendered flat colors without editable surface maps. Add all 17 optional standard/advanced HDR/PBR map slots, file browsing, image drops onto hit-tested meshes or hierarchy rows, and Texture children that apply to their immediate parent. Map edits, child moves, scene saves and undo/redo use the scene model. The shared editor/Play renderer samples authored/generated UVs and retains HDR values in half-float textures; external images are imported into project assets.

Extend the agent plugin with texture_inspect, texture_update, texture_create_child, environment_update and texture_guide. Live status includes direct/resolved maps and sky settings. Image/path/control validation precedes scene edits; initial child materials commit as one undoable edit. Install the focused rustic-textures skill for Codex and Claude while preserving customized stored skills. The bundled guide remains accessible through MCP independently of installed skill customizations.

GPU maps are capped at 1024 pixels per axis; displacement uses existing vertices and transmission approximates thin-surface lighting rather than refracted scene rendering. Included guides cover conventions, setup, exact tool arguments, asset portability, controls, verification and current limits.

Validation (Rust 1.99.1):

• World/editor-model tests passed, including map persistence, child resolution/reparenting, undo/redo, failure atomicity and read-only authoring.
• Editor regression suite: 81 passed, 1 existing test ignored. New live-tool flow covers partial updates, clearing, child creation/undo, HDR sky validation, saving and edit guards.
• Agent backend: 6 unit tests and 3 stdio integration tests passed. Workspace installation/migration: 6 passed, including texture skill discovery and customization preservation.
• Renderer including graphics tests: all 23 passed, covering HDR emission, all map bindings, UV offsets, lighting and selection outlines.
• Compile checks, Clippy across changed crates/all targets and formatting passed; existing deprecation/assertion-style warnings remain. UI dependencies resolve egui 0.36.1 consistently.

Outstanding release validation: the required Windows installer build cannot run on this Linux host (powershell is unavailable; the script requires Windows). Keep this PR in draft until a fresh Windows installer and a native file-dialog/drop walkthrough are validated.