evaluator.sx: 11 section headers + 27 subgroup/function comments
documenting the CEK machine structure (state, frames, kont ops,
extension points, eval utilities, machine core, special forms,
call dispatch, HO forms, continue phase, entry points).
mcp_tree.ml: sx_summarise and sx_read_tree now inject file comments
into their output — comments appear as un-numbered annotation lines
between indexed entries, so indices stay correct for editing.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>