Pairs with .gitattributes: eol=lf pins what git produces at checkout;
.editorconfig pins what editors write to disk - the one CRLF vector
git's filters cannot reach (git never rewrites the working tree, so an
editor-written CRLF file would persist with a clean status while the
doc gates misbehave on it). insert_final_newline declares the existing
one-trailing-newline policy (AGENTS.md, gated by git diff --check) at
the editor layer too.
(cherry picked from commit 7a09602fd76efff81a0875fb177289004c3dfc9b)
