fix: handle nested event loop in tool dispatch (fixes #11)

[awanawana]

Summary

• Fixes RuntimeError when using LightAgent inside FastAPI, Jupyter, or any async framework
• Adds run_async_safely() helper that detects event loop context and adapts execution strategy
• Zero breaking changes, backward compatible

Problem

When LightAgent is used inside an existing event loop (e.g., FastAPI), the current code calls asyncio.run() which raises:

RuntimeError: asyncio.run() cannot be called from a running event loop

This happens in two places:

• _run_non_stream_logic (line 868)
• _run_stream_logic (line 1054)

Solution

Introduce run_async_safely() that:

1. Checks if we're already in an event loop via asyncio.get_running_loop()
2. If not in a loop: use asyncio.run() as before (zero overhead)
3. If in a loop: run the coroutine in a ThreadPoolExecutor with its own event loop

This approach is:

• Framework agnostic: Works with FastAPI, Starlette, Quart, aiohttp, etc.
• Jupyter compatible: Works in notebooks where an event loop is always running
• Minimal overhead: Only creates a thread when actually needed
• Type safe: Preserves return type via TypeVar

Test Plan

• Verified original bug is reproduced with asyncio.run() inside event loop
• Verified fix works without existing event loop
• Verified fix works with existing event loop (FastAPI scenario)

Related

Fixes #11

🤖 Generated with Claude Code

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