- Add VERSION file as canonical version source
- build.sh reads VERSION file automatically, injects via -ldflags
- deploy.sh prompts for major/minor/patch bump, injects version via
ldflags into all 4 builds, and writes release/latest JSON file
- Add 'pulsewise-collector version' — prints version and checks for update
- Add 'pulsewise-collector update' — fetches and applies the latest release
- Default version changed to "dev" for local builds without ldflags
