#3741 stopped the always-on and Gemini writers from translating line endings
on write (newline=""), but every one of these paths still READ through
Path.read_text, which opens in universal-newline mode and folds CRLF to LF
before the block is merged. A later write then re-emitted the platform
default, so a read-modify-write normalised the WHOLE file: on Windows an LF
file gained CRLF on every line, on Linux a CRLF file lost its CR.
Install and uninstall now go through one shared read/write pair
(_read_keep_newline / _write_keep_newline): the file's own dominant ending is
detected on read, the section helpers keep working on bare-LF text, and the
ending is restored on write with newline="". A file with no prior convention
is written LF, matching the other writers. This covers claude_install,
_agents_install, codebuddy_install, gemini_install/_uninstall,
vscode_install/_uninstall, _strip_graphify_md_section, _agents_uninstall,
codebuddy_uninstall and _remove_claude_skill_registration, plus the two
#3741 paths so the read side can no longer drift from the write side.
Adds a round-trip test per writer: an LF file and a CRLF file in, same
endings out, and install-then-uninstall returns the exact original bytes.
(cherry picked from commit df5f032a62)
N. Hariharan
d2c1592eab