test(amlich): pin the golden fixture to LF

The table is compared byte-for-byte against output generated with \n, so
a Windows checkout with core.autocrlf=true rewrote the committed fixture
to CRLF and failed the comparison on that machine only — passing in CI,
and printing a diff whose two sides looked identical.

The pattern matches text extensions under testdata only: forcing text
conversion on a binary fixture would corrupt it.

.gitattributes

@@ -0,0 +1,8 @@
+# Golden fixtures are compared byte-for-byte against generated output, which
+# always writes LF. Without this, a Windows checkout (core.autocrlf=true)
+# rewrites them to CRLF and the comparison fails on that machine only — the
+# test passes in CI and fails locally, for a difference nothing prints.
+#
+# Text extensions only: a forced text conversion would corrupt a binary
+# fixture, so new binary testdata must not be matched here.
+**/testdata/**.txt text eol=lf