ci: make-pdf gate covers the diagram-render bundle; bundle pinned to LF

make-pdf-gate.yml paths gain lib/diagram-render/** and the drift test (a
bundle-only PR previously skipped every render gate AND no CI lane ran the
drift check at all). .gitattributes pins dist html/json to LF so Windows
autocrlf can't break the hash-pinned bundle.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.gitattributes

@@ -37,3 +37,9 @@ bin/*        text eol=lf
 *.gif        binary
 *.ico        binary
 *.pdf        binary
+
+# The committed diagram-render bundle is hash-pinned (BUILD_INFO sha256);
+# a CRLF rewrite on Windows checkout would break the drift test and change
+# the content-addressed staged filename.
+lib/diagram-render/dist/*.html text eol=lf
+lib/diagram-render/dist/*.json text eol=lf