Fix auto trader trades with additional item data

[PsyGuy007-sys]

What changed

• Match auto-trader inputs with the selected offer's ItemCost predicate.
• Extract the actual resource stored in each input slot, preserving its data components.
• Continue to enforce components explicitly required by an offer.
• Document the fix in the changelog.

Why

The auto trader previously converted the offer's displayed cost stack into an ItemResource and extracted it by exact resource equality. Items with additional data components, such as Productive Farming crops or the minecraft:custom_data example from #322, therefore failed to match even though vanilla villager trading accepts them.

Using ItemCost.test aligns automatic trading with MerchantOffer.satisfiedBy: additional components are allowed, while components required by the offer still have to match.

Impact

Auto traders can now consume otherwise valid trade inputs carrying additional data components. Multi-slot extraction and transactional rollback behavior are preserved.

Validation

• ./gradlew build
• Targeted regression check using carrots with minecraft:custom_data
• Verified that a mismatched explicitly required component is rejected
• Verified that an insufficient extraction is rolled back

Closes #322

[henkelmax]

Is this still WIP?