refactor: Rename fetch wrapper to middleware pattern

- Rename FetchWrapper type to FetchMiddleware for clarity
- Rename withWrappers() to applyMiddleware() following standard middleware patterns
- Update parameter names from 'fetch' to 'next' aligning with middleware conventions
- Update all test names and variables to use middleware terminology
- Add deprecation aliases for backward compatibility

This change makes the middleware pattern more recognizable to developers familiar with standard middleware systems like Express, Redux, etc.

Author: dsp-ant