environment-aware API usage

Always detect the runtime environment before using environment-specific APIs or utilities. This is crucial for networking applications that may run in browsers, Node.js servers, or cross-platform contexts.

Key practices:

1. Use platform-specific utilities when available (e.g., path.posix.join for consistent path handling)
2. Check for environment-specific globals before accessing them (e.g., typeof window !== 'undefined' && 'CSS' in window before using window.CSS.supports())
3. Use explicit module prefixes for built-in modules (e.g., "node:url" instead of "url" for Node.js built-ins)

Example of proper environment detection:

// Check for browser environment before using browser APIs
if (!this.isServer && typeof window !== 'undefined' && 'CSS' in window) {
  this.isViewTransitionTypesSupported = window.CSS.supports(...)
}

// Use Node.js module prefix for built-in modules
import { fileURLToPath } from 'node:url'

// Use platform-specific path utilities
path.posix.join(routesDirectoryFromRoot, v.filePath as string)

This approach prevents runtime errors and ensures your networking code works reliably across different deployment environments.