feat: terminate BrowserToolkit to allow rerun

[a7m-1st]

Description

A step to remedy camel-ai/owl#449 thus camel-ai/owl#450.

Playwright driver supports Async and Sync mode. Current BrowserToolkit is running in sync mode not async (see #1886). NotImplementedError is being thrown when trying to rerun OWL instance which is an error extensively discussed in microsoft/playwright-python#462, which seem to be caused by asyncio and Playwright sync version conflicts. But I will show you that this issue maynot look as it seems.

In my journey to fix "Building Society issue" related to Stop OWL Feature (see camel-ai/owl#450), I discovered that the NotImplementedError issue traces back to BrowserTookit reinstantiation in construct_society():

*BrowserToolkit(
	headless=False,  # Set to True for headless mode
	web_agent_model=models["browsing"],
	planning_agent_model=models["planning"],
).get_tools(),

While debugging, an Attribute Error exception was thrown when self.browser.close() was called before self.browser.init(). Thus the first commit.

Why _terminate() (Commit No.2)?

To demonstrate, Try to paste then run this code in browser_toolkit.py:

def test_sequential_browsers():
    from dotenv import load_dotenv

    from camel.models import ModelFactory
    from camel.types import ModelPlatformType, ModelType

    load_dotenv(dotenv_path="C:/Users/ASUS/camel/.env")

    """Test if we can initialize and use two browser instances sequentially."""
    print("Starting sequential browser test...")

    # First browser instance
    print("\n=== BROWSER INSTANCE #1 ===")
    models = {
        "browsing": ModelFactory.create(
            model_platform=ModelPlatformType.GEMINI,
            model_type=ModelType.GEMINI_2_5_PRO_EXP,
            model_config_dict={"temperature": 0},
        ),
        "planning": ModelFactory.create(
            model_platform=ModelPlatformType.GEMINI,
            model_type=ModelType.GEMINI_2_5_PRO_EXP,
            model_config_dict={"temperature": 0},
        ),
    }
    browser1 = BrowserToolkit(
        headless=False,
        web_agent_model=models["browsing"],
        planning_agent_model=models["planning"],
    )
    print("Initialized first")
    browser1.browser.init()
    browser1.browser.close()
    # browser1._terminate()

    browser2 = BrowserToolkit(
        headless=False,
        web_agent_model=models["browsing"],
        planning_agent_model=models["planning"],
    )
    browser2.browser.init()
    # browser2._terminate()
    print("Initialized second")
    print(
        "\nBoth browser instances have been initialized and closed successfully!"
    )


if __name__ == "__main__":
    test_sequential_browsers()

The above code should throw an error such as below. To fix the error below, uncomment # browser1._terminate() in between the instances. Playwright has a stop() function as in docs, thus it seems that you should stop() playwright before creating a new instance (at least in the sync mode).

playwright._impl._errors.Error: It looks like you are using Playwright Sync API inside the asyncio loop.    
Please use the Async API instead.

This is a step to fix the OWL error by drilling down the _terminate() function then calling it on OWL completion, but is still not complete on OWL's Termination edge cases, which I am polishing (see camel-ai/owl#450).

Checklist

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• I have linked this PR to an issue using the Development section on the right sidebar or by adding Fixes #issue-number in the PR description (required)
• I have checked if any dependencies need to be added or updated in pyproject.toml and uv lock
• I have updated the tests accordingly (required for a bug fix or a new feature)
• I have updated the documentation if needed:
• I have added examples if this is a new feature

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[a7m-1st]

TLDR;

1. Added _terminate() function for proper Playwright Termination
   -- To see the usefuless, copy and paste the code in browser_toolkit()
2. Fix Attribute Error in close() function