reorganize CLI with git-style commands and compact show output

Rename commands to match git conventions:
  inspect → show (alias: inspect)
  ls      → log  (alias: ls)
  store   → import (alias: store)
  extract → export (alias: extract)

Reorganize help into five categories: create, inspect, restore,
virtual machines, and signing/infrastructure. Shorten all about
strings. Set top-level about to "Compressed, deduplicated snapshots".

Replace verbose inspect output with compact five-line format:
  filename / format / size / parent / blocks / metadata summary.
Parse hexz_checkpoint metadata JSON for human-readable summary.
Full detail still available via --json.

Also: HEXZ_PASSWORD env var for non-interactive encryption,
clippy fixes (collapsible_else_if, unwrap_or_default),
fix test assertions for new output format.

Fixed failing python tests.

feat: Added `hexz ls` and `hexz diff` and refactored the old `hexz di…

…ff -> hexz overlay`

bug: Fixed tests being in the wrong crate forcing crates.io to not

publish.

refactor: Refactored the crates into a cleaner structure and remove

unneccesary dependencies.

Fixed failing tests from the CLI changes.

bug: Fixed add_bytes extra allocations by using an array instead of a…

… vec.

feat: Improved the CLI help output and added a few new examples.

feat: Added parallel packing and a progress bar so it is easier to know

if the packing is working and at what speed.

testing: Added new testing and fixed a minor performance issue.