v1.0.0 — Stock control that can prove its cost of goods

Most stock systems answer "how many" and shrug at "how much". Crate keeps the layers.

• Real FIFO with row locks — two simultaneous orders can never spend the same stock twice, and a shipment beyond the balance rolls back whole
• A cost you can defend: every shipment line stores its layers — lot, date, quantity taken, purchase price — next to the weighted-average alternative and the difference
• An immutable ledger: a mistake is fixed by a reversal that returns goods to the very lots they came from, and a receipt whose lot has already shipped cannot be reversed
• Transfers keep age and price, so moving stock does not reset the queue
• Stock counts that mean something: the sheet snapshots the expected quantity when it opens; surplus is received at the average cost, shortage written off through the queue
• Integers everywhere — money in kopecks, quantity in thousandths — and crate:verify reconciles balances with the ledger every night
• 40 tests on PostgreSQL, light and dark themes, README in three languages