fix(ci): force LF for claude-plugin bundle files

The skill-hygiene test asserts the claude-plugin bundle files are
byte-identical to the codex source, but .gitattributes only forced LF
for codex-plugin/ and cursor-plugin/. On Windows the claude-plugin
tree checks out CRLF, so claude_bundle_skills_stay_byte_identical_to_the_codex_source
fails. Cover claude-plugin/** too.

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

Author: ScriptedAlchemy

.gitattributes

@@ -6,6 +6,11 @@ tests/fixtures/** text eol=lf
 # them before the lint runs.
 codex-plugin/skills/** text eol=lf
 cursor-plugin/skills/** text eol=lf
+claude-plugin/** text eol=lf
+# Force LF for the retained agent source of truth; the bundle byte-identity
+# test compares claude-plugin agents against these files and Windows checkout
+# otherwise rewrites them to CRLF.
+src/agents/claude_agents/** text eol=lf
 # Force LF for embedded Hermes plugin template assets — they are pulled into
 # the binary via include_str! and the generated-plugin snapshot test asserts
 # their exact bytes.