build_index_sync uses asyncio.run() which fails in async context

[DeFiVC]

What

The build_index_sync function uses asyncio.run():

def build_index_sync(...) -> VectorStore:
    return asyncio.run(build_index(source_dir, output_path))

asyncio.run() creates a new event loop. If called from within an already-running event loop (e.g., from a FastAPI startup event or an async script), it raises RuntimeError: This event loop is closed.

Why

This limits where the function can be called from.

Scope

• Document the limitation
• Or use nest_asyncio / loop.run_until_complete for safer fallback

Acceptance Criteria

• The function works in both sync and async contexts
• Or the limitation is documented

Technical Context

• File: src/knowledge/index_builder.py, line 90

[OAKVISUALZ]

Please assign me this issue.