feat(lang): add node-specialist agent

[AliChishti]

Summary

• Add node-specialist - a senior Node.js backend developer specializing in high-performance APIs, CLIs, and microservices
• Masters the Node.js runtime, V8 engine internals, asynchronous patterns, streams, and event-driven architectures
• Perfect for building robust, highly scalable server-side JavaScript applications and background workers

Changes

• Created agent file categories/02-language-specialists/node-specialist.md
• Added entry to main README.md in the Language Specialists section
• Added detailed description in categories/02-language-specialists/README.md
• Added node-specialist to the Quick Selection Guide table
• Added node-specialist + typescript-pro to the "Enterprise Backend" pattern in Common Technology Stacks
• Added to categories/02-language-specialists/.claude-plugin/plugin.json
• Bumped version in .claude-plugin/marketplace.json for proper marketplace synchronization
• Updated subagent count badge (141)

What is node-specialist?

A Claude Code agent specializing in Node.js backend development, emphasizing deep ecosystem knowledge and best practices. Expertise includes the Node core modules (fs/promises, child_process, worker threads, async_hooks), the event loop lifecycle, handling I/O bound operations through streams and buffers, memory management, and implementing secure patterns (OWASP Top 10, dependency vetting).

Use cases:

• Building out fast, horizontally scalable REST and GraphQL APIs using Express, Fastify, or NestJS
• Designing robust microservice architectures involving message brokers (RabbitMQ, Kafka, BullMQ)
• Authoring performant CLI tools and executing background cron jobs effectively
• Streaming large files and datasets to prevent massive memory footprints during processing
• Diagnosing server crashes, tracing memory leaks, and profiling V8 garbage collection
• Securing backend endpoints with robust validation, rate-limiting, and error-boundary integrations