Function parse_quote_from_snapshot 

pub fn parse_quote_from_snapshot(
    snap: &PolymarketBookSnapshot,
    instrument_id: InstrumentId,
    price_precision: u8,
    size_precision: u8,
    ts_init: UnixNanos,
) -> Result<Option<QuoteTick>>

Extracts a top-of-book [QuoteTick] from a book snapshot.

Returns None if either side is empty.

Panics

Cannot panic: .expect() calls are guarded by the empty-side early return above.