Add Spirit Legacy TRELLIS production studio

[fcrowder84-web]

Adds a production-oriented browser GUI without replacing the existing ROCm app.py.

Key features:

• Front/Back/Left/Right/Top/Bottom/Extra 1/Extra 2 file selectors; source filenames do not matter.
• Generic 1-N image conditioning using stochastic or multidiffusion fusion, adapted locally from upstream TRELLIS.2 PR Add multi image referenece microsoft/TRELLIS.2#104 so the core ROCm pipeline remains untouched.
• Presets for the verified Phase-8 512 path plus preview/game/high-resolution experimental modes.
• Advanced sampler, seed, decimation, texture-size and token controls.
• Preserves the known-good gfx1201/ROCm 7.14/SDPA/flex_gemm environment and Phase-8 model-release-before-GLB lifecycle.
• Requires RGBA images with meaningful alpha to avoid the known BiRefNet ROCm failure path.
• Reproducible per-asset job folders with inputs, request, job state, metadata, log and GLB.
• Windows BAT launcher that starts the Ubuntu-hosted GUI over SSH and opens it in a browser.

The change is additive only: five new files, no modifications to the existing TRELLIS.2 ROCm code.