Add handler pipeline for network extraction

[frostbite-bot]

Summary

• add UnifiedStorageBeforeExtractHandler, mirroring the existing insertion pipeline
• route slot, key, fuzzy, and tag-based UnifiedStorage extraction through the new handler chain
• expose the handler to KubeJS scripts
• keep internal matter-compression rollback operations outside the public extraction pipeline
• cap transformed output to the amount actually available from the network

Closes #56.

Verification

• bash gradlew build
• git diff --check