watch and hook

watch

branxa watch [--interval <seconds>]

• polls Git change signature periodically
• auto-saves when signature changes
• default interval comes from config key watchInterval

hook

branxa hook install
branxa hook remove

• installs/removes only Branxa-managed post-commit block
• preserves unrelated custom hook lines

Key implementation

• src/commands/watch.ts
• src/commands/hook.ts