docs: the art check compares text, not bytes

The renderer's module docstring said a test can re-render and compare bytes.
That is not what happens. check_repo_art reads both sides with
Path.read_text, which applies universal-newline translation, so the comparison
is over text and a CRLF checkout passes either way.

The paragraph is the design rationale for check mode, so a reader deciding
whether to trust the gate reads exactly this claim. It now says what the check
does.

The byte-level reads are elsewhere and unchanged: the receipt records each
drawing's byte count and SHA-256 from read_bytes, which is why the art is
pinned to LF in .gitattributes.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: HarperZ9

scripts/render_repo_art.py

@@ -6,8 +6,8 @@
 The check mode is the point. Committed artwork drifts from the words it
 illustrates the moment someone edits one and not the other, and nobody
 notices, because a picture in a README is never diffed. Here the picture is
-a pure function of a spec that IS diffable, so a test can re-render and
-compare bytes.
+a pure function of a spec that IS diffable, so a test can re-render it and
+compare the result against what is committed.
 """
 from __future__ import annotations