Fix default database path to use nodes-v2.db

- Change default database path from nodes.db to nodes-v2.db
- This fixes the schema error when using NODE_DB_PATH from env
- Ensures consistency with the v2 implementation

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/services/node-documentation-service.ts

@@ -47,7 +47,7 @@ export class NodeDocumentationService {
   private docsFetcher: DocumentationFetcher;
   
   constructor(dbPath?: string) {
-    const databasePath = dbPath || process.env.NODE_DB_PATH || path.join(process.cwd(), 'data', 'nodes.db');
+    const databasePath = dbPath || process.env.NODE_DB_PATH || path.join(process.cwd(), 'data', 'nodes-v2.db');
     
     // Ensure directory exists
     const dbDir = path.dirname(databasePath);