fix(README): replace relative imports with absolute imports in quicks…

The quickstart examples used relative imports (e.g., from .activities) which fail when scripts are run directly with the error "attempted relative import with no known parent package".

What was changed

Changed relative imports to absolute imports README

Why?

Relative imports fail when Python scripts are executed directly (e.g., python run_worker.py) because Python doesn't recognize the script as part of a package. Using absolute imports allows the scripts to be run directly without import errors.

Checklist

1. Closes

2. How was this tested:

   • Ran python run_worker.py and verified it no longer throws ImportError: attempted relative import with no known parent package
   • Verified imports work correctly when running the script directly

3. Any docs updates needed? No docs updates needed.