Check if proposal generation is supported. Override this to return true when implementing real logic.
Generate proposals for a get_products request. Stub implementation returns empty array.
Publishers should override this to implement:
Refine an existing proposal based on new instructions. Stub implementation returns null.
Publishers should override this to implement:
Clean up expired proposals. Returns the number of proposals removed.
Stub implementation of ProposalManager. Uses in-memory storage and doesn't generate proposals.
Publishers should extend this class or provide their own implementation that integrates with their media planning systems or AI.