feat: add node: protocol to all Node.js built-in imports for bundler compatibility

- Updated all fs, path, crypto, os, url, util, events, http, https, net, child_process, stream, and zlib imports
- Changed both static imports and dynamic imports to use node: protocol
- This makes Brainy more bundler-friendly by explicitly marking Node.js built-ins
- Prevents bundlers from attempting to polyfill or bundle these modules
- Reduces bundle size for web applications using Brainy
- Improves tree-shaking and dead code elimination

Benefits for external bundlers:
- Clear distinction between Node.js built-ins and external dependencies
- No ambiguity about what needs polyfilling
- Smaller bundles for browser builds
- Better compatibility with modern bundlers (Webpack 5, Vite, Rollup, esbuild)

🤖 Generated with Claude Code

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

src/scripts/precomputePatternEmbeddings.ts

@@ -20,8 +20,8 @@
 
 import { Brainy } from '../brainy.js'
 import patternData from '../patterns/library.json' assert { type: 'json' }
-import * as fs from 'fs/promises'
-import * as path from 'path'
+import * as fs from 'node:fs/promises'
+import * as path from 'node:path'
 
 async function precomputeEmbeddings() {
   console.log('🧠 Pre-computing pattern embeddings...')