fix(shell): clean up rcfiles and remove redundancies

- Remove deprecated GREP_OPTIONS (handled via alias)
- Quote $ZSH_COMPDUMP to prevent word splitting
- Remove duplicate vim alias (nvim alias takes precedence)
- Consolidate completion path to ZSH_CUSTOM_COMPLETION_PATH
- Simplify PATH setup in rcfiles, centralize in exports
- Move LM Studio PATH from rcfiles to exports
- Add clarifying comments for macOS-specific ssh-add

base/bashrc

@@ -2,6 +2,7 @@
 # shellcheck shell=bash
 
 export DOTFILES="$HOME/.dotfiles"
+# Minimal PATH for x-have and utilities; full PATH set in shared.sh/exports
 export PATH="$HOME/.local/bin:$DOTFILES/local/bin:$PATH"
 export SHARED_SCRIPTS_SOURCED=0
 
@@ -11,7 +12,7 @@ source "$DOTFILES/config/shared.sh"
 [ -f "${DOTFILES}/config/fzf/fzf.bash" ] &&
   source "${DOTFILES}/config/fzf/fzf.bash"
 
-# Import ssh keys in keychain
+# Import ssh keys in keychain (macOS-specific -A flag, silently fails on Linux)
 ssh-add -A 2>/dev/null
 
 x-have antidot && {
@@ -22,5 +23,3 @@ PROMPT_DIRTRIM=3
 PROMPT_COMMAND='PS1_CMD1=$(git branch --show-current 2>/dev/null)'
 PS1='\[\e[95m\]\u\[\e[0m\]@\[\e[38;5;22;2m\]\h\[\e[0m\] \[\e[38;5;33m\]\w\[\e[0m\] \[\e[92;2m\]${PS1_CMD1}\n\[\e[39m\]➜\[\e[0m\] '
 
-# Added by LM Studio CLI (lms)
-export PATH="$PATH:$HOME/.lmstudio/bin"