install_stack runs webui-service.sh install on activate as well as rollback,
and that install refuses --board. A re-pin to a pre-198 copy would therefore
fail the same way a rollback did. console_for_target now drops the pair for
every op. The reason follows the target's cli.mjs: a target that parses
--board is pre-198 and the 7331 board is retired; one that does not runs the
board in the Console.
M13 covers a kept --board for a parsing target on activate --plan and on
rollback --plan. The webui README rollback note covers any move to a pre-198
copy. BUILD.md's Ruled section is updated to match.
UNVERIFIED: bash -n only; no node or tests run (Sage's gate).