The footgun class-fix left 23 files with unquoted encoding=utf-8-sig
(and main.py an f-string with nested double quotes) — SyntaxError /
NameError 'utf' at every import. Quoted all encoding values, re-verified
py_compile across every staged .py.
For each issue anchor present in BASE 63279301bc non-test .py and absent on HEAD, the BASE comment/docstring block was re-attached at the HEAD location of the code it explained (matched by the distinctive code line / enclosing def). Sentences already covered by an existing HEAD comment were deduped; the issue number always survives. Insert-only: no code lines changed.
