Settings saved via set_param() have no ir_model_data; the noupdate config XML
then collides on UNIQUE(key) during -u. Pre-migrate links existing params to
their XML external id (value-preserving) so upgrades are robust. Found on the
Entech clone-verify; affects prod (35 params vs 32 xmlids).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
