chore: ignore local Claude Code settings

Removes the accidentally-tracked .claude/settings.local.json (it's a
per-user IDE state file, not shared project config) and adds it to
.gitignore so it stays out of the repo on future commits.

Author: rustatian

.claude/settings.local.json

@@ -18,3 +18,4 @@
 .idea
 bench
 **vendor
+.claude/settings.local.json