case-insensitive plugins

by Karan Bansal

Stops `rm -rf content` silently destroying `Content` on case-insensitive filesystems (APFS default, exFAT, NTFS). A PreToolUse hook on Bash that resolves the real target of destructive commands (rm, rmdir, mv, mkdir, touch, find -delete) through cd/pushd chains, quotes, subshells, and heredocs, and denies the ones that would hit a differently-cased entry of what was typed. Three safety levels (HOOK_SAFETY_LEVEL), per-level ask mode instead of hard deny.