feat: gate action server config deploy

[nichenqin]

Summary

• add explicit server-config-deploy input for self-hosted Action Server Config Deploy
• fail before package/state mutation when /api/version does not advertise source package and server-side config bootstrap support
• map dry-run server config deploy to POST /api/action/deployments/from-config-package and document the mode

Verification

• bash -n scripts/install-appaloft.sh scripts/run-deploy.sh scripts/resolve-control-plane.sh

[nichenqin]

Closing this stacked PR in favor of #9, which syncs the complete self-host console bootstrap wrapper from appaloft/appaloft#203 in one PR.