feat(export): integrate 'Batch Export via encoderCraft' for procedural PBR texture maps and 3D material previews #27

Summary

Integrate MaterialCraft with encoderCraft (el-j/encoderCraft#1) via the shared ArtCraft inter-app dispatch protocol (craft-dispatch, storytold/craft-libs#505).

Scope

• Allow queuing procedural node-graph PBR texture map exports (Albedo, Normal, Roughness, Metallic, Height, Ambient Occlusion) at 2K/4K/8K resolutions to encoderCraft via IPC (/tmp/encodercraft-$UID.sock or loopback 127.0.0.1:8998).
• Support background batch encoding to 16-bit TIFF, half-float OpenEXR, lossless PNG, WebP, and 3D preview meshes (.glb, .usdz, .obj) without blocking node graph authoring.

Tracking & Cross-Links

• encoderCraft Master Tracking Issue: el-j/encoderCraft#1
• encoderCraft Repository: el-j/encoderCraft
• Shared Dispatch Protocol: storytold/craft-libs#505
• Shared Media Codecs: storytold/craft-libs#503 / storytold/craft-libs#504