Refactor RO-Crate support

[das-Abroxas]

Summary

Adds direct RO-Crate directory and ZIP ingestion to Pithos and replaces the local rocrate workspace crate with the upstream ro-crate-rs library.

Changes

• Introduces LoadedRoCrate with explicit directory and ZIP source tracking
• Streams ZIP members directly into Pithos without extracting them first
• Links physical data entries to the RO-Crate metadata entry
• Preserves ZIP file metadata, directories, and symlinks
• Rejects unsafe, overlapping, duplicate, encrypted, conflicting, and unsupported ZIP entries
• Corrects symlink extraction so targets cannot control where links are created
• Adds direct tests for filesystem and FastCDC utility functions
• Adds end-to-end directory/ZIP parity, multichunk streaming, path validation, and symlink extraction tests
• Updates documentation with ingestion examples and migration guidance
• Removes the obsolete local crates/rocrate implementation
• Bumps Pithos packages to 0.7.2
• Adds workspace tests, package validation, and publish dry runs to the tag release workflow