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/file_change_test.go

@@ -9,6 +9,7 @@ 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"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -53,7 +54,7 @@ func TestFileContentChange(t *testing.T) {
 	snapshotID1 := "snapshot1"
 	err = repos.WithTx(ctx, func(ctx context.Context, tx *sql.Tx) error {
 		snapshot := &database.Snapshot{
-			ID:             snapshotID1,
+			ID:             types.SnapshotID(snapshotID1),
 			Hostname:       "test-host",
 			VaultikVersion: "test",
 			StartedAt:      time.Now(),
@@ -87,7 +88,7 @@ func TestFileContentChange(t *testing.T) {
 	snapshotID2 := "snapshot2"
 	err = repos.WithTx(ctx, func(ctx context.Context, tx *sql.Tx) error {
 		snapshot := &database.Snapshot{
-			ID:             snapshotID2,
+			ID:             types.SnapshotID(snapshotID2),
 			Hostname:       "test-host",
 			VaultikVersion: "test",
 			StartedAt:      time.Now(),
@@ -117,12 +118,12 @@ func TestFileContentChange(t *testing.T) {
 	assert.Equal(t, newChunkHash, chunkFiles2[0].ChunkHash)
 
 	// Verify old chunk still exists (it's still valid data)
-	oldChunk, err := repos.Chunks.GetByHash(ctx, oldChunkHash)
+	oldChunk, err := repos.Chunks.GetByHash(ctx, oldChunkHash.String())
 	require.NoError(t, err)
 	assert.NotNil(t, oldChunk)
 
 	// Verify new chunk exists
-	newChunk, err := repos.Chunks.GetByHash(ctx, newChunkHash)
+	newChunk, err := repos.Chunks.GetByHash(ctx, newChunkHash.String())
 	require.NoError(t, err)
 	assert.NotNil(t, newChunk)
 
@@ -182,7 +183,7 @@ func TestMultipleFileChanges(t *testing.T) {
 	snapshotID1 := "snapshot1"
 	err = repos.WithTx(ctx, func(ctx context.Context, tx *sql.Tx) error {
 		snapshot := &database.Snapshot{
-			ID:             snapshotID1,
+			ID:             types.SnapshotID(snapshotID1),
 			Hostname:       "test-host",
 			VaultikVersion: "test",
 			StartedAt:      time.Now(),
@@ -208,7 +209,7 @@ func TestMultipleFileChanges(t *testing.T) {
 	snapshotID2 := "snapshot2"
 	err = repos.WithTx(ctx, func(ctx context.Context, tx *sql.Tx) error {
 		snapshot := &database.Snapshot{
-			ID:             snapshotID2,
+			ID:             types.SnapshotID(snapshotID2),
 			Hostname:       "test-host",
 			VaultikVersion: "test",
 			StartedAt:      time.Now(),