Remove policyengine-us-data from the certified bundle package scaffold

[anth-volk]

The current certified bundle manifest still treats policyengine-us-data as an installable package component even though certified US datasets now come from the Populace data release manifest path.

This causes bundle package verification and release asset generation to include policyengine-us-data, which can fail publication when the package is not installed or no longer belongs in the current package scaffold.

Expected behavior:

• The current bundle package scaffold should include policyengine, policyengine-core, policyengine-us, and policyengine-uk.
• policyengine-us-data should not be emitted in current bundle install requirements or release constraints.
• Historical manifests, provenance, and legacy references may continue to mention policyengine-us-data where they describe older artifacts.
• Bundle metadata checks and package-only verification should not require policyengine-us-data.