Introduce tui.Version (defaults to "dev"), stamped at build time via a VERSION_LDFLAG in the Makefile (-X .../internal/tui.Version=$(VERSION)) across all build targets. main.go handles "--version"/"-v" before launching the TUI, and the version is shown next to the title in the header. Docs updated (README + CLAUDE). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>