refactor: Migrate to pnpm monorepo with clean 3-layer architecture

- Implement Ports and Adapters pattern with full separation of concerns
- Split codebase into three packages:
  * @starfleet/data-core: Pure business logic with zero Node.js dependencies
  * @starfleet/data-host-node: Node.js adapters implementing core ports
  * @starfleet/data-cli: Thin presentation layer with composition root
- Migrate from npm to pnpm for monorepo management
- Add workspace configuration with pnpm-workspace.yaml
- Configure .npmrc for optimal pnpm workspace behavior
- Implement runtime port validation with ensurePort
- Use workspace:* protocol for local package dependencies
- Add proper package exports with /* patterns for directory mapping
- Establish clean dependency injection via composition root
- Convert remaining CommonJS modules to ESM
- Ensure all tests pass with new architecture

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

Co-Authored-By: Claude <[email protected]>

Author: flyingrobots

src/lib/config.js

@@ -2,10 +2,10 @@
  * Configuration management for data CLI
  */
 
-const fs = require('fs').promises;
-const path = require('path');
-const os = require('os');
-const { safeParsedataConfig, mergeConfigs } = require('./schemas/dataConfigSchema');
+import { promises as fs } from 'fs';
+import path from 'path';
+import os from 'os';
+import { safeParsedataConfig, mergeConfigs } from './schemas/dataConfigSchema.js';
 
 /**
  * Configuration class for data CLI
@@ -220,4 +220,4 @@ class Config {
   }
 }
 
-module.exports = Config;
+export default Config;