v1.4.0

Minor release: two parser-hardening improvements to the Bash auto-approve classifier, plus docs.

• feat: treat heredoc bodies as opaque data by @karlkfi in #31
• feat: recognize pure substitutions in auto-approved git chains by @karlkfi in #30
• docs: document autoUpdate opt-in for the third-party marketplace by @karlkfi in #29
• docs: note Autofix wake-up interaction with auto-allowed pushes by @karlkfi in #25
• docs: point already-installed users from Install to Upgrade by @karlkfi in #23

Full Changelog: v1.3.1...v1.4.0