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/chunks_test.go

@@ -3,6 +3,8 @@ package database
 import (
 	"context"
 	"testing"
+
+	"git.eeqj.de/sneak/vaultik/internal/types"
 )
 
 func TestChunkRepository(t *testing.T) {
@@ -14,7 +16,7 @@ func TestChunkRepository(t *testing.T) {
 
 	// Test Create
 	chunk := &Chunk{
-		ChunkHash: "chunkhash123",
+		ChunkHash: types.ChunkHash("chunkhash123"),
 		Size:      4096,
 	}
 
@@ -24,7 +26,7 @@ func TestChunkRepository(t *testing.T) {
 	}
 
 	// Test GetByHash
-	retrieved, err := repo.GetByHash(ctx, chunk.ChunkHash)
+	retrieved, err := repo.GetByHash(ctx, chunk.ChunkHash.String())
 	if err != nil {
 		t.Fatalf("failed to get chunk: %v", err)
 	}
@@ -46,7 +48,7 @@ func TestChunkRepository(t *testing.T) {
 
 	// Test GetByHashes
 	chunk2 := &Chunk{
-		ChunkHash: "chunkhash456",
+		ChunkHash: types.ChunkHash("chunkhash456"),
 		Size:      8192,
 	}
 	err = repo.Create(ctx, nil, chunk2)
@@ -54,7 +56,7 @@ func TestChunkRepository(t *testing.T) {
 		t.Fatalf("failed to create second chunk: %v", err)
 	}
 
-	chunks, err := repo.GetByHashes(ctx, []string{chunk.ChunkHash, chunk2.ChunkHash})
+	chunks, err := repo.GetByHashes(ctx, []string{chunk.ChunkHash.String(), chunk2.ChunkHash.String()})
 	if err != nil {
 		t.Fatalf("failed to get chunks by hashes: %v", err)
 	}