[hygiene] Add .gitattributes — CRLF/LF churn pollutes the synced bundle and diffs

[stancsz]

Severity: High (for a sync product) — architect review (2026-06-20).

There is no .gitattributes. Every commit warns LF will be replaced by CRLF. This is not cosmetic:

• The OKF bundle is the synced artifact, and its selling point is being human-readable and diffable. CRLF/LF drift across devices produces spurious whole-file diffs and merge noise in exactly the files users sync between machines.
• It already caused unreadable full-file diffs when porting tooling between repos.

Acceptance criteria

• Add a .gitattributes normalizing line endings (* text=auto eol=lf) for .py/.md/.sql and marking binaries.
• Re-normalize the working tree once (git add --renormalize .).
• Document the expectation that exported bundles use LF so cross-device diffs stay clean.