fix(mise): correct PATH precedence, error handling, and shell detection

- Append non-mise PATH entries so mise shims keep highest precedence
- Remove legacy cargo bin from initial PATH bootstrap
- Detect current shell for mise activate instead of hardcoding bash
- Rename AWS_SESSION_TOKEN to AWS_SESSION_TOKEN_FILE (was a file path)
- Add exit-on-failure checks to dfm mise install block
- Fix reset_nvim to call mise instead of removed npm installer
- Forward all args in dfm mise-cleanup
- Auto-detect DOTFILES in cleanup script when not pre-exported
- Report brew uninstall failures instead of masking with || true
- Fix p10k segment name from MISE to ASDF
- Replace npm with yarn in CLAUDE.md Bash whitelist

scripts/cleanup-old-version-managers.sh

@@ -4,6 +4,11 @@ set -euo pipefail
 # This script targets specific known directories — NOT which/command -v,
 # because nvim's Mason installs some of the same tool names.
 #
+# Ensure DOTFILES is set even when script is invoked directly
+if [ -z "${DOTFILES:-}" ]; then
+  DOTFILES="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+  export DOTFILES
+fi
 # shellcheck source=shared.sh
 source "$DOTFILES/config/shared.sh"
 
@@ -113,8 +118,11 @@ if command -v brew &> /dev/null; then
       else
         msgr run "Uninstalling brew package: $pkg"
         msgr warn "Note: $pkg may have dependents"
-        brew uninstall "$pkg" || true
-        msgr run_done "Uninstalled $pkg"
+        if brew uninstall "$pkg"; then
+          msgr run_done "Uninstalled $pkg"
+        else
+          msgr err "Failed to uninstall $pkg"
+        fi
       fi
     fi
   done