Redirects PageUp and PageDown keys to scroll the conversation window while typing in the input field.
当前为 
--- Explanation of Changes ---
 The original script fixed issues with the PageUp, PageDown, Home, and End keys in ChatGPT but had unintended side effects:
 1. **Home and End Keys Issue**:
    - It intercepted the `Home` and `End` keys globally, including in text fields, breaking default browser shortcuts like `Ctrl + Home` and `Shift + End`.
    - This was problematic for users relying on standard Windows/browser behavior.
 2. **Focus Interference**:
    - The script required the user to click outside the input field for PageUp and PageDown to work, disrupting workflow.
 3. **Redundant Logic**:
    - The original code contained duplicated logic for finding the scrollable container and handling key events, making it harder to maintain.
 **How This Version Fixes These Issues**:
 - **Preserves Home and End Behavior**: Home and End keys now retain their default functionality.
 - **Focus-Free Scrolling**: PageUp and PageDown work directly on the conversation window, even when typing in the input field.
 - **Improved Readability**: Functions are now modular and descriptive, with no redundant checks or duplication.
 - **Minimal Interference**: Only PageUp and PageDown are intercepted; all other keys behave as expected.
 This approach ensures compatibility with standard shortcuts while fixing the scrolling issues.