Add .gitattributes: LF in the repository, CRLF for batch files

Normalize the files that had been committed with CRLF (line endings only,
no content changes).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.gitattributes

@@ -0,0 +1,14 @@
+# Keep LF in the repository regardless of the OS that edits the files.
+* text=auto eol=lf
+
+# cmd.exe needs CRLF in batch files
+*.bat text eol=crlf
+*.cmd text eol=crlf
+
+*.png binary
+*.jpg binary
+*.webp binary
+*.ogg binary
+*.wav binary
+*.zip binary
+*.rpa binary