v0.0.10 - support for file format version 3

2025-07-16 0.0.10 release

• Added support for file format version 3 (v3)
  • Use -F 3 option to generate v3 files
  • Default remains v1 for compatibility
• v3 includes updated signature scheme with stronger algorithms (see README for details)
• Decryption automatically detects format version

Note: In the upcoming 1.0.0 release, the default output format will switch to v3.
Please test v3 using the -F 3 option in this release.

See #34 for the overall migration plan.