refactor(theme-studio): extract control factories to controls.js, drop dead previewFaceAttrs

I split the custom dropdown, detail-editor, and expander factories out of app.js into controls.js (205 lines), spliced back at a CONTROLS_J token by generate.py. The token sits at the exact extraction point, so the assembled page is byte-identical and every gate passes unchanged. app.js drops from 927 to 721 lines.

I also removed previewFaceAttrs (function, export, and test). It was test-only dead code whose docstring stalely claimed the gate calls it. The gate uses assertPreviewFaces instead.

0 files changed, 0 insertions, 0 deletions