Package Modules with explicit dependencies and safe activation defaults

[LeftTwixWand]

Outcome

Define signed, portable Module packages with explicit dependencies and conservative activation behavior.

Acceptance criteria

• Include contracts, capability Neurons, concrete Behaviors, BDD, standard Surfaces, host metadata, and optional renderer extensions in the signed package.
• Allow at most one safe UI Behavior to auto-enable.
• Keep all other Behaviors disabled by default.
• Require a portable fallback for every renderer extension.

Non-goals

• Treating a Module as a runtime process or auto-enabling non-UI Behaviors.