fix: improve shell detection, curl flags, and cleanup robustness

- Use ZSH_VERSION instead of ZSH_NAME for reliable zsh detection
- Document NVIM_* env vars as optional external overrides
- Add -fsSL flags to curl for mise bootstrap
- Consolidate duplicate shellcheck directives in install-fonts.sh
- Add explicit return 0 to cleanup script helper functions
- Add actionable remediation to uv-not-found error message

scripts/install-fonts.sh

@@ -51,7 +51,6 @@ install_fonts()
 {
   msgr run "Starting to install NerdFonts..."
   # shellcheck disable=SC2048,SC2086
-  # shellcheck disable=SC2086
   ./install.sh -q -s ${fonts[*]} \
     && msgr run_done "Done"
   return 0