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/models.go

@@ -2,22 +2,27 @@
 // It includes types for files, chunks, blobs, snapshots, and their relationships.
 package database
 
-import "time"
+import (
+	"time"
+
+	"git.eeqj.de/sneak/vaultik/internal/types"
+)
 
 // File represents a file or directory in the backup system.
 // It stores metadata about files including timestamps, permissions, ownership,
 // and symlink targets. This information is used to restore files with their
 // original attributes.
 type File struct {
-	ID         string // UUID primary key
-	Path       string
+	ID         types.FileID     // UUID primary key
+	Path       types.FilePath   // Absolute path of the file
+	SourcePath types.SourcePath // The source directory this file came from (for restore path stripping)
 	MTime      time.Time
 	CTime      time.Time
 	Size       int64
 	Mode       uint32
 	UID        uint32
 	GID        uint32
-	LinkTarget string // empty for regular files, target path for symlinks
+	LinkTarget types.FilePath // empty for regular files, target path for symlinks
 }
 
 // IsSymlink returns true if this file is a symbolic link.
@@ -30,16 +35,16 @@ func (f *File) IsSymlink() bool {
 // Large files are split into multiple chunks for efficient deduplication and storage.
 // The Idx field maintains the order of chunks within a file.
 type FileChunk struct {
-	FileID    string
+	FileID    types.FileID
 	Idx       int
-	ChunkHash string
+	ChunkHash types.ChunkHash
 }
 
 // Chunk represents a data chunk in the deduplication system.
 // Files are split into chunks which are content-addressed by their hash.
 // The ChunkHash is the SHA256 hash of the chunk content, used for deduplication.
 type Chunk struct {
-	ChunkHash string
+	ChunkHash types.ChunkHash
 	Size      int64
 }
 
@@ -51,13 +56,13 @@ type Chunk struct {
 // The blob creation process is: chunks are accumulated -> compressed with zstd
 // -> encrypted with age -> hashed -> uploaded to S3 with the hash as filename.
 type Blob struct {
-	ID               string     // UUID assigned when blob creation starts
-	Hash             string     // SHA256 of final compressed+encrypted content (empty until finalized)
-	CreatedTS        time.Time  // When blob creation started
-	FinishedTS       *time.Time // When blob was finalized (nil if still packing)
-	UncompressedSize int64      // Total size of raw chunks before compression
-	CompressedSize   int64      // Size after compression and encryption
-	UploadedTS       *time.Time // When blob was uploaded to S3 (nil if not uploaded)
+	ID               types.BlobID   // UUID assigned when blob creation starts
+	Hash             types.BlobHash // SHA256 of final compressed+encrypted content (empty until finalized)
+	CreatedTS        time.Time      // When blob creation started
+	FinishedTS       *time.Time     // When blob was finalized (nil if still packing)
+	UncompressedSize int64          // Total size of raw chunks before compression
+	CompressedSize   int64          // Size after compression and encryption
+	UploadedTS       *time.Time     // When blob was uploaded to S3 (nil if not uploaded)
 }
 
 // BlobChunk represents the mapping between blobs and the chunks they contain.
@@ -65,8 +70,8 @@ type Blob struct {
 // their position and size within the blob. The offset and length fields
 // enable extracting specific chunks from a blob without processing the entire blob.
 type BlobChunk struct {
-	BlobID    string
-	ChunkHash string
+	BlobID    types.BlobID
+	ChunkHash types.ChunkHash
 	Offset    int64
 	Length    int64
 }
@@ -75,18 +80,18 @@ type BlobChunk struct {
 // This is used during deduplication to identify all files that share a chunk,
 // which is important for garbage collection and integrity verification.
 type ChunkFile struct {
-	ChunkHash  string
-	FileID     string
+	ChunkHash  types.ChunkHash
+	FileID     types.FileID
 	FileOffset int64
 	Length     int64
 }
 
 // Snapshot represents a snapshot record in the database
 type Snapshot struct {
-	ID                   string
-	Hostname             string
-	VaultikVersion       string
-	VaultikGitRevision   string
+	ID                   types.SnapshotID
+	Hostname             types.Hostname
+	VaultikVersion       types.Version
+	VaultikGitRevision   types.GitRevision
 	StartedAt            time.Time
 	CompletedAt          *time.Time // nil if still in progress
 	FileCount            int64
@@ -108,13 +113,13 @@ func (s *Snapshot) IsComplete() bool {
 
 // SnapshotFile represents the mapping between snapshots and files
 type SnapshotFile struct {
-	SnapshotID string
-	FileID     string
+	SnapshotID types.SnapshotID
+	FileID     types.FileID
 }
 
 // SnapshotBlob represents the mapping between snapshots and blobs
 type SnapshotBlob struct {
-	SnapshotID string
-	BlobID     string
-	BlobHash   string // Denormalized for easier manifest generation
+	SnapshotID types.SnapshotID
+	BlobID     types.BlobID
+	BlobHash   types.BlobHash // Denormalized for easier manifest generation
 }