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/scanner_test.go

@@ -10,6 +10,7 @@ import (
 	"git.eeqj.de/sneak/vaultik/internal/database"
 	"git.eeqj.de/sneak/vaultik/internal/log"
 	"git.eeqj.de/sneak/vaultik/internal/snapshot"
+	"git.eeqj.de/sneak/vaultik/internal/types"
 	"github.com/spf13/afero"
 )
 
@@ -74,7 +75,7 @@ func TestScannerSimpleDirectory(t *testing.T) {
 	snapshotID := "test-snapshot-001"
 	err = repos.WithTx(ctx, func(ctx context.Context, tx *sql.Tx) error {
 		snapshot := &database.Snapshot{
-			ID:               snapshotID,
+			ID:               types.SnapshotID(snapshotID),
 			Hostname:         "test-host",
 			VaultikVersion:   "test",
 			StartedAt:        time.Now(),
@@ -209,7 +210,7 @@ func TestScannerLargeFile(t *testing.T) {
 	snapshotID := "test-snapshot-001"
 	err = repos.WithTx(ctx, func(ctx context.Context, tx *sql.Tx) error {
 		snapshot := &database.Snapshot{
-			ID:               snapshotID,
+			ID:               types.SnapshotID(snapshotID),
 			Hostname:         "test-host",
 			VaultikVersion:   "test",
 			StartedAt:        time.Now(),