FRE-600: Implement Phase 1 WebSocket + Yjs CRDT foundation

- Create TypeScript and Vite configuration for SolidJS
- Implement Yjs document structure for screenplay collaboration
- Build WebSocket connection manager with exponential backoff reconnection
- Create CRDT document manager with undo/redo support
- Set up WebSocket sync server with JWT authentication
- Add SolidJS reactive bindings for Yjs shared types
- Build collaborative editor component
- Write unit tests for CRDT operations
- Document implementation in analysis/fre600_websocket_foundation.md

Architecture: Yjs chosen over Automerge for better ecosystem and
Tauri compatibility. WebSocket for sync, WebRTC for video.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

src/lib/collaboration/crdt-document.ts

@@ -0,0 +1,137 @@
+/**
+ * CRDT Document Manager
+ * Coordinates Yjs document lifecycle, persistence, and sync
+ */
+
+import { Doc, Text, Map as YMap, UndoManager } from 'yjs';
+import { WebSocketConnection, WebSocketConnectionManager } from './websocket-connection';
+import { createScreenplayDoc, getOrCreateSharedTypes, ScreenplayMetadata } from './yjs-document';
+
+export interface CRDTDocumentManager {
+  initialize(projectId: string, serverUrl: string, authToken: string): Promise<Doc>;
+  getText(type: string): Text;
+  getMetadata(): ScreenplayMetadata;
+  getProvider(): any; // WebSocketProvider
+  applyRemoteUpdate(update: Uint8Array, origin: string): void;
+  createUndoStack(): UndoManager;
+  createRedoStack(): UndoManager;
+  destroy(): void;
+}
+
+export class CRDTDocument implements CRDTDocumentManager {
+  private doc: Doc | null = null;
+  private connection: WebSocketConnectionManager | null = null;
+  private undoManager: UndoManager | null = null;
+  private redoManager: UndoManager | null = null;
+  private projectId: string | null = null;
+
+  async initialize(
+    projectId: string,
+    serverUrl: string,
+    authToken: string
+  ): Promise<Doc> {
+    this.projectId = projectId;
+
+    // Create Yjs document
+    this.doc = createScreenplayDoc(projectId, {});
+
+    // Initialize WebSocket connection
+    this.connection = new WebSocketConnection({
+      serverUrl,
+      documentName: `project-${projectId}`,
+      authToken,
+      reconnectInterval: 1000,
+      maxReconnectInterval: 30000,
+    });
+
+    // Connect to WebSocket server
+    await this.connection.connect();
+
+    // Get the provider to access the synced document
+    const provider = this.connection.getProvider();
+    
+    // Sync local document with remote state
+    // Yjs WebSocketProvider handles this automatically on connect
+    
+    // Initialize undo/redo managers
+    const sharedTypes = getOrCreateSharedTypes(this.doc);
+    this.undoManager = new UndoManager([sharedTypes.text], {
+      captureTimeout: 1000,
+    });
+
+    this.redoManager = new UndoManager([sharedTypes.text], {
+      captureTimeout: 1000,
+    });
+
+    return this.doc;
+  }
+
+  getText(type: string = 'main'): Text {
+    if (!this.doc) {
+      throw new Error('Document not initialized. Call initialize() first.');
+    }
+    return this.doc.getText(type);
+  }
+
+  getMetadata(): ScreenplayMetadata {
+    if (!this.doc) {
+      throw new Error('Document not initialized. Call initialize() first.');
+    }
+    const meta = this.doc.getMap<ScreenplayMetadata>('metadata');
+    return meta.toJSON() as ScreenplayMetadata;
+  }
+
+  getProvider(): any {
+    if (!this.connection) {
+      throw new Error('Connection not initialized. Call initialize() first.');
+    }
+    return this.connection.getProvider();
+  }
+
+  applyRemoteUpdate(update: Uint8Array, origin: string): void {
+    if (!this.doc) {
+      throw new Error('Document not initialized.');
+    }
+    
+    // Apply the update to the document
+    // Yjs handles the CRDT merge automatically
+    this.doc.applyUpdate(update, origin);
+  }
+
+  createUndoStack(): UndoManager {
+    if (!this.undoManager) {
+      throw new Error('Document not initialized. Call initialize() first.');
+    }
+    return this.undoManager;
+  }
+
+  createRedoStack(): UndoManager {
+    if (!this.redoManager) {
+      throw new Error('Document not initialized. Call initialize() first.');
+    }
+    return this.redoManager;
+  }
+
+  destroy(): void {
+    if (this.undoManager) {
+      this.undoManager.destroy();
+      this.undoManager = null;
+    }
+    
+    if (this.redoManager) {
+      this.redoManager.destroy();
+      this.redoManager = null;
+    }
+
+    if (this.connection) {
+      this.connection.disconnect();
+      this.connection = null;
+    }
+
+    if (this.doc) {
+      this.doc = null;
+    }
+
+    this.projectId = null;
+  }
+}