run_backtest changed from async to sync function. Pipeline refresh
(async) runs via asyncio.run() before the sync BacktestRunner,
avoiding nested event loop when SnapshotStore.load() calls asyncio.run().
CLI updated to call run_backtest() directly (no asyncio.run wrapper).
Tested: `fithia2 paper backtest --config v6new.24 --start 2025-03-23 --end 2026-03-23` works.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
I Luk Kim