Durable contracts for the new turn/session runtime, shared by core and
renderer:
- turns.ts: zod schemas for all 16 durable turn events, TurnContext
(previousTurnId ref | inline messages), ModelRequest with contextRef
and current-turn-only messages, ephemeral delta types, reduceTurn
enforcing every spec invariant, and pure derivations
(deriveTurnStatus, turnTranscript, outstanding work).
- sessions.ts: session_created/turn_appended/title_changed schemas,
reduceSession, and the SessionIndexEntry projection.
- vitest wiring for packages/shared (config, build-excluded tests);
92 tests covering happy paths, recovery-shaped histories, and one
named test per corruption invariant.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
