samebytes 0.1.0

First release: economicspace's tree_check.py, platform_check.py and
.githooks/ (as of economicspace 087aef5), with the comparison functions of
its verify.py, made into a package. The commits that built the three moved
files are replayed at the start of this repository's history, limited to
those files; frames.py starts from a verbatim AST extraction so that its
first diff is the whole of what changed.

What changed in moving it:

• The repository is an argument. tree_check.py checked the directory it
  sat in; installed, that is site-packages, so verify_tree(repo) and
  assert_tree(repo, label) take it and nothing defaults it except the
  command line (the current directory).
• parity takes its reference path and its advice. The reference file and
  the four project phrases the report prints (HINTS: the re-baseline
  command, the record command, where the dtype traps and the hashes are
  written down) are arguments. The probes and their argument grids are
  unchanged, so a reference recorded by economicspace stays comparable.
  Proved: with economicspace's hints, report prints byte-identical output to
  platform_check.py on all-match, libm, pandas, hard-defect and combined
  references, and collect() is identical.
• frames is verify.py's comparison as public functions:
  comparable, canonical_csv, frame_hash, column_diff, blanks,
  read_exact, float_hash. The provenance columns are a drop= argument.
  Proved against verify.py on 108 baseline cells: the same frame, hash,
  canonical CSV and column diff for every one.
• One behavioural difference: blanks accepts pd.NA. verify.py's
  version raised "boolean value of NA is ambiguous" on the nullable string
  dtype; it never met one. On every input verify.py accepted, the results are
  the same.
• read_exact refuses a float_precision argument rather than obeying
  it, and passes every other read_csv argument through.
• hooks: install copies the sh hooks into a repository and sets
  core.hooksPath .githooks; check compares the copies byte for byte and
  asks git for the eol=lf pin and the executable bit. The hook's header now
  names samebytes instead of economicspace's CLAUDE.md.
• python -m samebytes tree | parity | hooks install/check.

Tests: the stale same-length read git cannot see, the absent file, CRLF
through .gitattributes, the skip that must not pass; each frames rule; the
parity buckets and the pinned probe grids; every hooks finding and the hook
itself leaving a real edit alone. Sixteen of the bugs behind them are planted
in a copy of the package and shown to fail their test.