chore(cache): Add .gitignore for certificate files

Prevent certificate files from being accidentally committed to the repository.

Signed-off-by: kaikaila <[email protected]>

Author: kaikaila

backend/src/cache/certs/.gitignore

@@ -0,0 +1,9 @@
+# Ignore certificate files - these should never be committed
+*.pem
+*.key
+*.crt
+*.p12
+*.pfx
+
+# Keep this .gitignore file
+!.gitignore