Add custom types, version command, and restore --verify flag

- Add internal/types package with type-safe wrappers for IDs, hashes,
  paths, and credentials (FileID, BlobID, ChunkHash, etc.)
- Implement driver.Valuer and sql.Scanner for UUID-based types
- Add `vaultik version` command showing version, commit, go version
- Add `--verify` flag to restore command that checksums all restored
  files against expected chunk hashes with progress bar
- Remove fetch.go (dead code, functionality in restore)
- Clean up TODO.md, remove completed items
- Update all database and snapshot code to use new custom types

internal/snapshot/snapshot.go

@@ -54,6 +54,7 @@ import (
 	"git.eeqj.de/sneak/vaultik/internal/database"
 	"git.eeqj.de/sneak/vaultik/internal/log"
 	"git.eeqj.de/sneak/vaultik/internal/storage"
+	"git.eeqj.de/sneak/vaultik/internal/types"
 	"github.com/dustin/go-humanize"
 	"github.com/spf13/afero"
 	"go.uber.org/fx"
@@ -90,20 +91,35 @@ func (sm *SnapshotManager) SetFilesystem(fs afero.Fs) {
 	sm.fs = fs
 }
 
-// CreateSnapshot creates a new snapshot record in the database at the start of a backup
+// CreateSnapshot creates a new snapshot record in the database at the start of a backup.
+// Deprecated: Use CreateSnapshotWithName instead for multi-snapshot support.
 func (sm *SnapshotManager) CreateSnapshot(ctx context.Context, hostname, version, gitRevision string) (string, error) {
+	return sm.CreateSnapshotWithName(ctx, hostname, "", version, gitRevision)
+}
+
+// CreateSnapshotWithName creates a new snapshot record with an optional snapshot name.
+// The snapshot ID format is: hostname_name_timestamp or hostname_timestamp if name is empty.
+func (sm *SnapshotManager) CreateSnapshotWithName(ctx context.Context, hostname, name, version, gitRevision string) (string, error) {
 	// Use short hostname (strip domain if present)
 	shortHostname := hostname
 	if idx := strings.Index(hostname, "."); idx != -1 {
 		shortHostname = hostname[:idx]
 	}
-	snapshotID := fmt.Sprintf("%s_%s", shortHostname, time.Now().UTC().Format("2006-01-02T15:04:05Z"))
+
+	// Build snapshot ID with optional name
+	timestamp := time.Now().UTC().Format("2006-01-02T15:04:05Z")
+	var snapshotID string
+	if name != "" {
+		snapshotID = fmt.Sprintf("%s_%s_%s", shortHostname, name, timestamp)
+	} else {
+		snapshotID = fmt.Sprintf("%s_%s", shortHostname, timestamp)
+	}
 
 	snapshot := &database.Snapshot{
-		ID:                 snapshotID,
-		Hostname:           hostname,
-		VaultikVersion:     version,
-		VaultikGitRevision: gitRevision,
+		ID:                 types.SnapshotID(snapshotID),
+		Hostname:           types.Hostname(hostname),
+		VaultikVersion:     types.Version(version),
+		VaultikGitRevision: types.GitRevision(gitRevision),
 		StartedAt:          time.Now().UTC(),
 		CompletedAt:        nil, // Not completed yet
 		FileCount:          0,
@@ -652,7 +668,7 @@ func (sm *SnapshotManager) CleanupIncompleteSnapshots(ctx context.Context, hostn
 			log.Info("Cleaning up incomplete snapshot record", "snapshot_id", snapshot.ID, "started_at", snapshot.StartedAt)
 
 			// Delete the snapshot and all its associations
-			if err := sm.deleteSnapshot(ctx, snapshot.ID); err != nil {
+			if err := sm.deleteSnapshot(ctx, snapshot.ID.String()); err != nil {
 				return fmt.Errorf("deleting incomplete snapshot %s: %w", snapshot.ID, err)
 			}
 
@@ -661,7 +677,7 @@ func (sm *SnapshotManager) CleanupIncompleteSnapshots(ctx context.Context, hostn
 			// Metadata exists - this snapshot was completed but database wasn't updated
 			// This shouldn't happen in normal operation, but mark it complete
 			log.Warn("Found snapshot with S3 metadata but incomplete in database", "snapshot_id", snapshot.ID)
-			if err := sm.repos.Snapshots.MarkComplete(ctx, nil, snapshot.ID); err != nil {
+			if err := sm.repos.Snapshots.MarkComplete(ctx, nil, snapshot.ID.String()); err != nil {
 				log.Error("Failed to mark snapshot as complete in database", "snapshot_id", snapshot.ID, "error", err)
 			}
 		}