Restore uncommitted work from earlier sessions: DMX scene-select channels,
MQTT override handling, configurable zone refresh interval, OSC additions,
and matching tests and docs.
Add versioning following nginx-cache-purge: VERSION file, ldflags-stamped
build identifiers in info.go, Makefile, GoReleaser config, GitHub workflows,
and a -version flag using the standard flag package.
Claude-Session: https://claude.ai/code/session_01C5ZxhELATettecwYcNiXVN
