In Python package: - Allow configuring initial contribution state as parameter `initial_state: dict[str, Any]` passed to `Contribution()` In TypeScript package: - Remove `title` and `visible` properties from `Contribution` - Add `container?: S` to `Contribution<S>` - let action `updateContributionContainer()` only change `Contribution.container` - Allow callbacks to change contribution state - Allow contribution state changes to trigger callback invocations See #20