Function parse_quote_from_price_change 

pub fn parse_quote_from_price_change(
    quote: &PolymarketQuote,
    instrument_id: InstrumentId,
    price_precision: u8,
    size_precision: u8,
    price_increment: Price,
    drop_quotes_missing_side: bool,
    last_quote: Option<&QuoteTick>,
    ts_event: UnixNanos,
    ts_init: UnixNanos,
) -> Result<Option<QuoteTick>>

Parses a quote tick from a price change message using its best_bid/best_ask fields.

Returns None when either top-of-book side is absent or at the resolution boundary and drop_quotes_missing_side is enabled. Returns None for locked or crossed top-of-book prices. Uses the changed level’s size when it matches the reported top on that side. Otherwise, carries each previous size only when its price still matches the reported top; moved or unknown sides have zero size.