Summary

Expose MOON_TASK_CONTENT_HASH to task child processes.

This hash uses Moon’s task-local and toolchain hash material, but excludes upstream dependency task result hashes. Moon’s existing cache behavior remains unchanged and continues to use MOON_TASK_HASH for hydrate/archive/remote cache behavior.

This gives external command wrappers a Moon-native static key for runtime-observed cache experiments without requiring them to reimplement Moon’s task hashing logic.

Changes

• Generate both the full task hash and task content hash during task hash generation
• Preserve dependency edge identity in the content hash while excluding dependency result hash values
• Inject MOON_TASK_CONTENT_HASH alongside MOON_TASK_HASH
• Add tests for env injection and dep-hash exclusion behavior
• Document the new env var in cache docs