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/database/files_test.go

@@ -53,7 +53,7 @@ func TestFileRepository(t *testing.T) {
 	}
 
 	// Test GetByPath
-	retrieved, err := repo.GetByPath(ctx, file.Path)
+	retrieved, err := repo.GetByPath(ctx, file.Path.String())
 	if err != nil {
 		t.Fatalf("failed to get file: %v", err)
 	}
@@ -81,7 +81,7 @@ func TestFileRepository(t *testing.T) {
 		t.Fatalf("failed to update file: %v", err)
 	}
 
-	retrieved, err = repo.GetByPath(ctx, file.Path)
+	retrieved, err = repo.GetByPath(ctx, file.Path.String())
 	if err != nil {
 		t.Fatalf("failed to get updated file: %v", err)
 	}
@@ -99,12 +99,12 @@ func TestFileRepository(t *testing.T) {
 	}
 
 	// Test Delete
-	err = repo.Delete(ctx, nil, file.Path)
+	err = repo.Delete(ctx, nil, file.Path.String())
 	if err != nil {
 		t.Fatalf("failed to delete file: %v", err)
 	}
 
-	retrieved, err = repo.GetByPath(ctx, file.Path)
+	retrieved, err = repo.GetByPath(ctx, file.Path.String())
 	if err != nil {
 		t.Fatalf("error getting deleted file: %v", err)
 	}
@@ -137,7 +137,7 @@ func TestFileRepositorySymlink(t *testing.T) {
 		t.Fatalf("failed to create symlink: %v", err)
 	}
 
-	retrieved, err := repo.GetByPath(ctx, symlink.Path)
+	retrieved, err := repo.GetByPath(ctx, symlink.Path.String())
 	if err != nil {
 		t.Fatalf("failed to get symlink: %v", err)
 	}