feat: add interactive app server protocol

[oratis]

Summary

• add versioned structured tool, usage, approval, and user-input protocol events
• bind interaction responses to the active thread, turn, request id, and request kind
• release pending interactions on interrupt/shutdown and reject stale responses
• pass model, effort, and mode through the trusted RuntimeHost executor
• persist completed approval and user-input outcomes while keeping live requests transient

Validation

• pre-commit format, lint, typecheck, and all workspace tests passed
• 951 TypeScript tests passed / 12 skipped
• protocol recorder tests prove all interactive/tool/usage activity is excluded from durable replay
• server contract tests cover approval, user input, stale responses, structured events, and interruption while waiting

Stack

Base: #189

[oratis]

Review: approved ✅

Interaction events are where a protocol usually grows races, and the binding rules here address the ones that matter.

What I checked

• Responses are bound to thread + turn + request id + request kind. The kind component is the non-obvious one and it's the right call: id-only binding lets a stale approval response satisfy a different kind of pending request that happens to reuse an id. Requiring the kind to match makes that unrepresentable.
• Pending interactions are released on interrupt and shutdown. Otherwise interrupt during a pending approval leaves a promise nobody will ever settle and a client waiting on a dialog that can never resolve.
• Stale responses are rejected rather than applied late — the reconnect/double-click case.
• Model, effort, and mode pass through the trusted RuntimeHost executor, not directly from client input. That keeps Runtime safety: mandatory policy and real cancellation #181's invariant intact: a client can express a preference, it cannot assert policy.
• Completed approval and user-input outcomes persist; live requests stay transient. Consistent with feat: define experimental runtime protocol #186's persistence rule, and it means a resumed thread shows what was decided without resurrecting a dialog for a decision already made.

Versioning these as capability-negotiated structured events (rather than free-form payloads) is what lets #197/#203/#205 keep extending the protocol additively.

Validation: CI green; full suite green locally at the stack tip.