Datary 0.2.1: preserve checked-in session integrity

[devkyato]

Why this patch exists

Oh! The post-publication verification did exactly what it was supposed to do: it found that Git normalized the example session's CSV from CRLF to LF after the manifest hash had been generated. The data still parsed, but the checked-in evidence no longer verified byte-for-byte.

I did not want to wave that away as “only an example.” This focused patch makes every Datary CSV writer choose LF explicitly, regenerates the example session, and adds a byte-level regression assertion.

Verification

• example session passes datary doctor after Git normalization
• example data.csv contains no CRLF bytes
• 87 tests pass; one Windows symlink test skips when the OS denies symlink creation
• 79.75% coverage against the enforced 75% floor
• Ruff and strict Mypy pass
• clean 0.2.1 wheel records and verifies a session
• wheel and source distribution build successfully
• no analytical or parser behavior changed

Release status

This remains an alpha prerelease. It is a narrow evidence-integrity correction following the broader 0.2.0 audit.