Add Yjs document and provider infrastructure with tests

[wmxscott]

Summary

This PR introduces the core Yjs (CRDT) infrastructure for Ratifyd, including document initialization, shared type definitions, provider setup, and React context integration. All new code is fully tested with comprehensive unit and integration tests.

Key Changes

• src/lib/yjs/doc.ts: Core Yjs document factory and shared types accessor

  • createYjsDoc(): Creates isolated Y.Doc instances
  • getSharedTypes(): Centralized accessor for all 8 shared CRDT types (Maps, Arrays, Text)
  • TypeScript interfaces for SharedTypes, AdmittedPeer, and EncryptedChatEntry
  • Comprehensive documentation of encryption boundaries (moderatorChat/Notes are encrypted; editorContent/excalidrawState are not)

• src/lib/yjs/providers.ts: WebRTC and IndexedDB provider initialization

  • initProviders(): Sets up y-webrtc and y-indexeddb with proper room naming
  • Returns indexeddbSynced promise to gate peer admission until local state is restored
  • Cleanup via destroy() method

• src/lib/yjs/YjsContext.tsx: React context and hooks for Yjs access

  • YjsProvider: Wraps app with Yjs state; blocks rendering until IndexedDB syncs
  • useYjs(): Hook to access ydoc, shared types, and webrtc provider
  • Enforces admission gate: children only render after local persistence is ready

• Test files (3 new test suites):

  • doc.test.ts: 13 tests covering document creation, shared type instantiation, and cross-doc sync
  • providers.test.ts: 8 tests verifying provider construction, room naming, and lifecycle
  • YjsContext.test.tsx: 9 tests for React integration, loading states, and context consumption

• Config updates:

  • vitest.config.ts: Added .test.tsx pattern support
  • package.json: Added @testing-library/react and @testing-library/jest-dom dev dependencies

Notable Implementation Details

• Admission gate: YjsProvider does not render children until indexeddbSynced resolves, preventing race conditions where owner's burnedJTIs or trustedSigningKeys are not yet loaded when peers connect
• Encryption boundaries: Clearly documented which shared types contain encrypted data (moderatorChat, moderatorNotes) vs. plaintext (editorContent, excalidrawState)
• Type safety: Full TypeScript support with generic types for Y.Map and Y.Array
• Provider cleanup: Proper resource management with destroy callbacks on unmount

https://claude.ai/code/session_01AWujUF4neyha29dXbquNKZ