feat(waiter): Enhance terminal content waiting utility with fluent API and multi-pattern support

- Implement Playwright-inspired fluent API for more expressive test code
- Add wait_for_any_content and wait_for_all_content for composable waiting
- Fix type annotations for all wait_for functions
- Improve WaitResult class to handle different return types
- Fix doctest examples to prevent execution failures
- Enhance error handling with better timeout messages

Author: tony