feat: Inline contexts for all evaluation events

[keelerm84]

The v4 event schema is being broadened to accept full context payloads instead of only the context kind/key pairings.

There are several additional commits coming to address the updated spec, so these PRs are going to be merged into a feature branch.

[shortcut-integration[bot]]

This pull request has been linked to Shortcut Story #223829: Inline contexts for evals events.