Merge origin/main: resolve conflicts in CLI surface, --prune, helpers

- Adopt origin's SnapshotPurgeOptions naming and PurgeSnapshotsWithOptions
  method, but extend with Names []string (repeatable --snapshot flag) and
  Quiet bool for use by --prune.
- Adopt origin's parseSnapshotName helper.
- Fold the duplicate post-backup prune block into one runPostBackupPrune
  call that filters retention to the snapshot names just backed up.
- Keep the shallow-verify timestamp parsing fix and the dead deep-verify
  branch removal; use origin's printVerifyHeader/verifyManifestBlobsExist
  helper extraction.
- Drop top-level vaultik purge and verify (duplicates of snapshot purge
  and snapshot verify).
- Drop the resurrected daemon block from info.go (config fields no
  longer exist).
- Combine Makefile targets: gofmt -l for fmt-check, -race for tests,
  release/release-snapshot/docker/hooks/deps/test-coverage all included.

docs/DATAMODEL.md

@@ -23,7 +23,6 @@ Stores metadata about files in the filesystem being backed up.
 - `id` (TEXT PRIMARY KEY) - UUID for the file record
 - `path` (TEXT NOT NULL UNIQUE) - Absolute file path
 - `mtime` (INTEGER NOT NULL) - Modification time as Unix timestamp
-- `ctime` (INTEGER NOT NULL) - Change time as Unix timestamp  
 - `size` (INTEGER NOT NULL) - File size in bytes
 - `mode` (INTEGER NOT NULL) - Unix file permissions and type
 - `uid` (INTEGER NOT NULL) - User ID of file owner