v0.3.0

Added

• snapshot create [name] subcommand: explicit snapshot creation with optional name.
• snapshot list subcommand: shows available snapshots, excluding system subvolumes.
• snapshot delete <name> subcommand: refuses fstab-referenced system subvolumes. Mounted-subvolume and default-subvolume protection delegated to kernel and btrfs-progs.
• --help and -h at top level and for snapshot subcommands.

Changed

• snapshot <name> replaced by snapshot create <name>. Bare snapshot (no args) still creates with the default name. Unrecognized snapshot subcommands are now rejected instead of silently treated as snapshot names.

Fixed

• Migration step 1 now handles all fstab device reference formats (UUID=, LABEL=, /dev/ paths). Previously only UUID= was supported.