Move all worker-facing record types (TaskListRecord, RuntimeTaskRecord,
TeamRecord, MailboxSummary, FeedItemRecord, LibraryAppRecord, etc.)
into protocol-owned mirrors in records.rs. The gateway and worker_client
now use these protocol types instead of importing from the runtime crate.
Add worker-protocol/ with OpenAPI spec and JSON schemas as the
language-neutral contract authority for the gateway-worker boundary.
This is the migration surface for the TS worker replacement.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>