security: fix path traversal in plugin_rm, add coding tools

- prevent path traversal in ais plugin rm (reject .. and /)
- validate plugin_add requires user/repo format
- extract list_plugins() helper to deduplicate code
- add git aliases (s, d, l, lg, pa for dual push, etc)
- add cargo/rg aliases and mkcd helper to zshrc
- fix zr alias (source instead of unreachable exec)

.zshrc

@@ -12,9 +12,23 @@ alias v="vim"
 alias ts="vim ~/.tmux.conf"
 alias vs="vim ~/.vimrc"
 alias zs="vim ~/.zshrc"
-alias zr="exec $SHELL && . ~/.zshrc"
+alias zr="source ~/.zshrc"
 alias ll="ls -alh"
 alias df="df -H"
+alias g="git"
+alias gs="git s"
+alias gd="git d"
+alias gl="git l"
+alias gp="git pa"
+alias cb="cargo build --release"
+alias cr="cargo run"
+alias ct="cargo test"
+
+# mkcd: create and enter directory
+mkcd() { mkdir -p "$1" && cd "$1" }
+
+# rg shortcut with common defaults
+r() { rg --smart-case --hidden --glob '!.git' "$@" }
 
 zmodload zsh/complist
 zstyle ':completion:*' menu select