Day 65 — CSV Writer: Appending Fills to the Master Trade Log

Your engine got OOM-killed at 09:31:14 mid-append to master_trade_log.csv. The last fill’s row never got its trailing newline. The next fill wrote right after it, on the same line.

What you’re building

AppendOnlyCSVWriter and its companion CorruptionQuarantine boundary. The writer serializes every append behind an asyncio.Lock, builds each row as one comp…