feat: add browser environment compatibility support

- Remove top-level Node.js imports that break bundlers
- Use universal adapters for crypto operations
- Add dynamic imports for Node.js-specific modules
- Add browser field to package.json for bundler hints
- Maintain full Node.js functionality while enabling browser usage

This allows Brainy to be used with modern bundlers (Vite, Webpack, etc.)
without requiring Node.js polyfills. Browser environments get core features
while Node.js retains all capabilities including filesystem and networking.

package.json

@@ -41,6 +41,11 @@
       "types": "./dist/universal/index.d.ts"
     }
   },
+  "browser": {
+    "./dist/distributed": false,
+    "./dist/cli": false,
+    "./dist/scripts": false
+  },
   "engines": {
     "node": "22.x"
   },