fix(spaces): add missing custom nodes for GGUF / preprocessors / math / mxToolkit

fix(spaces): pin custom nodes to SHAs (also fixes LTXVideo's master default)

fix(spaces): _git_clone uses init+fetch so SHA refs work

fix(spaces): use \$HOME instead of /data (no persistent-storage add-on needed)

feat(spaces): registry entries for renamed BF16 aliases + seed inputs + bootstrap

feat: API-format workflows + sidebar nav + responsive UI

ci: run unit tests + ruff lint on every push

feat(app): generate handler — async streaming, status banner, video output

feat(app): per-mode forms with media inputs, presets, advanced accordion

feat(app): Gradio shell with sidebar nav and empty mode tabs