- Add UUID field to both inner and outer manifest messages
- Generate random v4 UUID when creating manifest
- Hash compressed data (not uncompressed) for integrity check
- Verify hash before decompression to prevent malicious payloads
- Validate UUIDs are proper format and match between inner/outer
- Sign string format: MAGIC-UUID-MULTIHASH
Use zstd with SpeedBestCompression level for better compression
ratios. Remove gzip support entirely. Include generated protobuf
file to allow building without protoc.
