Implement CLI skeleton with cobra and fx dependency injection

- Set up cobra CLI with all commands (backup, restore, prune, verify, fetch)
- Integrate uber/fx for dependency injection and lifecycle management
- Add globals package with build-time variables (Version, Commit)
- Implement config loading from YAML with validation
- Create core data models (FileInfo, ChunkInfo, BlobInfo, Snapshot)
- Add Makefile with build, test, lint, and clean targets
- Include minimal test suite for compilation verification
- Update documentation with --quick flag for verify command
- Fix markdown numbering in implementation TODO

internal/models/models.go

@@ -0,0 +1,73 @@
+package models
+
+import (
+	"time"
+)
+
+// FileInfo represents a file in the backup system
+type FileInfo struct {
+	Path  string
+	MTime time.Time
+	Size  int64
+}
+
+// ChunkInfo represents a content-addressed chunk
+type ChunkInfo struct {
+	Hash   string // SHA256 hash
+	Size   int64
+	Offset int64 // Offset within source file
+}
+
+// ChunkRef represents a reference to a chunk in a blob or file
+type ChunkRef struct {
+	ChunkHash string
+	Offset    int64
+	Length    int64
+}
+
+// BlobInfo represents an encrypted blob containing multiple chunks
+type BlobInfo struct {
+	Hash       string    // Hash of encrypted blob
+	FinalHash  string    // Hash after compression and encryption
+	CreatedAt  time.Time
+	Size       int64
+	ChunkCount int
+}
+
+// Snapshot represents a backup snapshot
+type Snapshot struct {
+	ID           string    // ISO8601 timestamp
+	Hostname     string
+	Version      string
+	CreatedAt    time.Time
+	FileCount    int64
+	ChunkCount   int64
+	BlobCount    int64
+	TotalSize    int64
+	MetadataSize int64
+}
+
+// SnapshotMetadata contains the full metadata for a snapshot
+type SnapshotMetadata struct {
+	Snapshot   *Snapshot
+	Files      map[string]*FileInfo
+	Chunks     map[string]*ChunkInfo
+	Blobs      map[string]*BlobInfo
+	FileChunks map[string][]*ChunkRef // path -> chunks
+	BlobChunks map[string][]*ChunkRef // blob hash -> chunks
+}
+
+// Chunk represents a data chunk for processing
+type Chunk struct {
+	Data   []byte
+	Hash   string
+	Offset int64
+	Length int64
+}
+
+// DirtyPath represents a path marked for backup by inotify
+type DirtyPath struct {
+	Path      string
+	MarkedAt  time.Time
+	EventType string // "create", "modify", "delete"
+}