strict mode flag

As a convenience we allow non-web actions to still be called.
Some devs may want us to more closely follow what Runtime does.

Add a --strict flag to run in strict mode

Start at the dev command entry point and inspect how command-line options are defined and how non-web actions are currently allowed. Compare that behavior with Runtime's strict mode, then add the --strict flag so the dev command follows it; verify the flag and its effect with the existing CLI checks, if available.

Written by the indexing model from the issue text.