Restores the gate (reverts the full-removal commit) and bypasses it in
non-production environments instead. The motivation for the original
removal — local source-built daemons report a `git describe` version
like v0.2.15-N-gHASH that parses below 0.2.20 and blocks dev testing —
is now handled by checking APP_ENV on the server and NODE_ENV on the
client. Production keeps the original "needs upgrade" UX.
Co-authored-by: multica-agent <github@multica.ai>