Modular Encryption V2

[kiloOhm]

Rebuilt from current master as suggested in #654

Summary

Adds Parquet Modular Encryption support to parquet-dotnet across the reader and writer paths.

What changed

• Added public encryption and decryption configuration through ParquetOptions.
• Supports AES_GCM_V1 and AES_GCM_CTR_V1.
• Supports encrypted footers and signed plaintext footers.
• Supports uniform footer-key encryption and per-column keys.
• Supports 128-, 192-, and 256-bit AES keys.
• Supports stored and externally supplied AAD prefixes.
• Added key resolution through direct keys or IParquetKeyRetriever.
• Encrypts and decrypts footers, column metadata, page headers, and page bodies.
• Allows reading available plaintext/projected columns without every column key.
• Added decryption-aware ReadSchemaAsync overloads.
• Fails closed on wrong keys, tampered modules, mismatched AAD prefixes, and unknown configured column paths.
• Explicitly rejects appending to encrypted files, which is not supported yet.

Interoperability and testing

• Added parquet-java/parquet-mr interoperability coverage.
• Added external fixture coverage across:
  • both encryption algorithms
  • encrypted and plaintext footer modes
  • stored, supplied, and absent AAD prefixes
  • uniform and partial column encryption
  • 128- and 256-bit keys
  • key metadata configurations
• Replaced the committed 79 MB inspector JAR with pinned, reviewable Java source built by Maven in CI.
• Added DuckDB interop test Encryption support (footer key) #726

Validation completed with:

dotnet test src/Parquet.slnx -c Release --no-restore
895 passed, 3 skipped, 0 failed

[kiloOhm]

Just read the LLM rule. Closing