Fix/browser initialization, improved UI

[ManojINaik]

This PR improves browser initialization and navigation handling:

• Improved browser launch and initialization with updated settings
• Enhanced error handling and logging
• Fixed page initialization to avoid navigation conflicts
• Added proper cleanup of resources
• Improved context creation and state management
• Added event listeners for popup handling

These changes make the browser more stable and reliable when handling navigation and page transitions.

[warmshao]

Hi, thank you for your PR. However, your commits have the following issues:

1. You removed content from the main branch to resolve conflicts. Specifically, you deleted relevant information from the README. When resolving merge conflicts, it's crucial to carefully integrate changes and avoid deleting content from the target branch unintentionally.

2. You deleted or modified things that didn't need changes. For example, you removed the .env.example file (which is important) and removed the emoji from the print statements (I actually like that emoji). Please only make changes that are necessary and directly related to the feature or bug fix you're addressing.

3. You claimed to have "Improved browser launch and initialization with updated settings" and "Fixed page initialization to avoid navigation conflicts," and then made significant changes to CustomBrowser and CustomBrowserContext. However, I haven't encountered these issues myself. Before making such substantial changes, you need to demonstrate that these problems actually exist. Then we can discuss whether the changes are necessary. Your modifications make it difficult to expand in the future. You can refer to this PR: https://github.com/warmshao/browser-use-webui/pull/16, which is relatively much cleaner.

4. Additionally, please try to limit each Pull Request to a single feature. This makes it much easier for me to review.

Thank you again!

[CLAassistant]

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