feat(toolbox-llamaindex): Enable sync and async context management for ToolboxClient

[anubhav756]

Similar to #308

This PR enhances ToolboxClient to support both synchronous and asynchronous context managers, improving its flexibility and ensuring proper resource management.

Users can now manage the client's lifecycle using either pattern:

Sync Usage

with ToolboxClient("...") as toolbox:
    # Client is automatically closed here
    ...

Async Usage:

async with ToolboxClient("...") as toolbox:
    # Client is automatically closed here
    ...

Additionally, a close() method has been added to automatically clean up underlying HTTP sessions when the client is garbage collected, preventing potential resource leaks.

[twishabansal]

Have we decide to close user provided sessions too?

[anubhav756]

Have we decide to close user provided sessions too?

To clarify, assuming you're asking whether this implementation might incorrectly close a session provided by the user, the answer is no.

We intentionally do not close sessions that are provided by the user (i.e., not managed internally). This is handled by a check in the core library here.

In the specific context of toolbox-llamaindex, this situation doesn't arise. To support both sync and async methods, we need to run async calls in a background loop/thread. This loop isn't accessible to the user, so the ToolboxClient must always create and manage the session object internally. As a result, there's no mechanism for a user to provide their own session in these packages.

Therefore, the scenario of a user-provided session being incorrectly closed by the client won't happen in toolbox-llamaindex.

Let me know if you have any other questions!