Remove ref symlink (now a local directory with daemon refs), gitignore CLAUDE.md

ref/ was a symlink to p2pool-merged-v36. Now restructured as:
  ref/p2pool -> p2pool-merged-v36
  ref/daemons/{litecoin,dogecoin,digibyte,bitcoin,namecoin} -> local clones
All under existing ref/ gitignore rule.

Author: frstrtr

.gitignore

@@ -83,3 +83,4 @@ ref/
 
 # Local test launch scripts (contain credentials)
 /run-testnet.sh
+CLAUDE.md