**feat: add browser-compatible build configuration and environment detection**

### Changes:
- Added `rollup.unified.js` for building a unified bundle with environment detection (Node.js, Browser, Serverless).
- Added `rollup_config.js` for browser-specific bundle configurations.
- Created `tsconfig.browser.json` for browser builds and `tsconfig.unified.json` for unified builds.
- Implemented custom Rollup plugins:
  - **`fixThisReferences`**: Resolves `this` reference issues in TensorFlow files.
  - **`nodeModuleShims`**: Provides empty shims for Node.js built-in modules in browser environments.
- Updated dependencies in `package-lock.json` to include Rollup plugins and updated `buffer` dependency for polyfills.
- Created `src/unified.ts` as the unified library entry point with dynamic environment detection.

### Purpose:
- Introduced a unified and browser-compatible build pipeline to ensure `Brainy` can seamlessly operate across multiple environments (Node.js, Browser, Serverless).
- Resolved compatibility issues with Node.js modules and specific library builds.
- Enhanced flexibility and usability for developers working in diverse runtime environments.

rollup_config.js

@@ -0,0 +1,98 @@
+import typescript from '@rollup/plugin-typescript'
+import resolve from '@rollup/plugin-node-resolve'
+import commonjs from '@rollup/plugin-commonjs'
+import json from '@rollup/plugin-json'
+import { terser } from 'rollup-plugin-terser'
+
+// Custom plugin to fix 'this' references in specific files
+const fixThisReferences = () => {
+  return {
+    name: 'fix-this-references',
+    transform(code, id) {
+      // Only transform the specific files that have issues with 'this'
+      if (id.includes('@tensorflow/tfjs-layers/dist/layers/convolutional_recurrent.js')) {
+        // Replace 'this' with 'globalThis' in the problematic code
+        return {
+          code: code.replace(/\bthis\b/g, 'globalThis'),
+          map: { mappings: '' } // Provide an empty sourcemap to avoid warnings
+        };
+      }
+      return null; // Return null to let Rollup handle other files normally
+    }
+  };
+};
+
+// Custom plugin to provide empty shims for Node.js built-in modules
+const nodeModuleShims = () => {
+  return {
+    name: 'node-module-shims',
+    resolveId(source) {
+      // List of Node.js built-in modules to shim
+      const nodeBuiltins = [
+        'fs', 'path', 'util', 'crypto', 'os', 'stream', 
+        'http', 'http2', 'https', 'zlib', 'child_process'
+      ];
+
+      if (nodeBuiltins.includes(source)) {
+        // Return a virtual module ID for the shim
+        return `\0${source}-shim`;
+      }
+      return null;
+    },
+    load(id) {
+      // If this is one of our shims, return an empty module
+      if (id.startsWith('\0') && id.endsWith('-shim')) {
+        console.log(`Providing empty shim for Node.js module: ${id.slice(1, -5)}`);
+        return 'export default {}; export const promises = {};';
+      }
+      return null;
+    }
+  };
+};
+
+export default {
+  input: 'examples/browser_compatible_exports.ts', // Browser-compatible entry point
+  inlineDynamicImports: true,
+  output: [
+    {
+      file: 'dist/brainy.js',
+      format: 'es',
+      sourcemap: true,
+      intro: 'var global = typeof window !== "undefined" ? window : this;',
+    },
+    {
+      file: 'dist/brainy.min.js',
+      format: 'es',
+      sourcemap: true,
+      intro: 'var global = typeof window !== "undefined" ? window : this;',
+      plugins: [terser()]
+    }
+  ],
+  plugins: [
+    // Add our custom plugins first to ensure they run before other transformations
+    fixThisReferences(),
+    nodeModuleShims(),
+    resolve({
+      browser: true,
+      preferBuiltins: false
+    }),
+    commonjs({
+      transformMixedEsModules: true
+    }),
+    json(),
+    typescript({
+      tsconfig: './tsconfig.browser.json',
+      declaration: false,
+      declarationMap: false
+    })
+  ],
+  external: [
+    // Add any dependencies you want to exclude from the bundle
+    // AWS SDK modules with circular dependencies
+    '@aws-sdk/client-s3',
+    '@smithy/util-stream',
+    '@smithy/node-http-handler',
+    '@aws-crypto/crc32c'
+    // Node.js built-ins are now handled by the nodeModuleShims plugin
+  ]
+}