Add exclude patterns, snapshot prune, and other improvements

- Implement exclude patterns with anchored pattern support:
  - Patterns starting with / only match from root of source dir
  - Unanchored patterns match anywhere in path
  - Support for glob patterns (*.log, .*, **/*.pack)
  - Directory patterns skip entire subtrees
  - Add gobwas/glob dependency for pattern matching
  - Add 16 comprehensive tests for exclude functionality

- Add snapshot prune command to clean orphaned data:
  - Removes incomplete snapshots from database
  - Cleans orphaned files, chunks, and blobs
  - Runs automatically at backup start for consistency

- Add snapshot remove command for deleting snapshots

- Add VAULTIK_AGE_SECRET_KEY environment variable support

- Fix duplicate fx module provider in restore command

- Change snapshot ID format to hostname_YYYY-MM-DDTHH:MM:SSZ

internal/snapshot/snapshot.go

@@ -46,6 +46,7 @@ import (
 	"io"
 	"os/exec"
 	"path/filepath"
+	"strings"
 	"time"
 
 	"git.eeqj.de/sneak/vaultik/internal/blobgen"
@@ -91,7 +92,12 @@ func (sm *SnapshotManager) SetFilesystem(fs afero.Fs) {
 
 // CreateSnapshot creates a new snapshot record in the database at the start of a backup
 func (sm *SnapshotManager) CreateSnapshot(ctx context.Context, hostname, version, gitRevision string) (string, error) {
-	snapshotID := fmt.Sprintf("%s-%s", hostname, time.Now().UTC().Format("20060102-150405Z"))
+	// Use short hostname (strip domain if present)
+	shortHostname := hostname
+	if idx := strings.Index(hostname, "."); idx != -1 {
+		shortHostname = hostname[:idx]
+	}
+	snapshotID := fmt.Sprintf("%s_%s", shortHostname, time.Now().UTC().Format("2006-01-02T15:04:05Z"))
 
 	snapshot := &database.Snapshot{
 		ID:                 snapshotID,
@@ -688,15 +694,16 @@ func (sm *SnapshotManager) deleteSnapshot(ctx context.Context, snapshotID string
 
 	// Clean up orphaned data
 	log.Debug("Cleaning up orphaned records in main database")
-	if err := sm.cleanupOrphanedData(ctx); err != nil {
+	if err := sm.CleanupOrphanedData(ctx); err != nil {
 		return fmt.Errorf("cleaning up orphaned data: %w", err)
 	}
 
 	return nil
 }
 
-// cleanupOrphanedData removes files, chunks, and blobs that are no longer referenced by any snapshot
-func (sm *SnapshotManager) cleanupOrphanedData(ctx context.Context) error {
+// CleanupOrphanedData removes files, chunks, and blobs that are no longer referenced by any snapshot.
+// This should be called periodically to clean up data from deleted or incomplete snapshots.
+func (sm *SnapshotManager) CleanupOrphanedData(ctx context.Context) error {
 	// Order is important to respect foreign key constraints:
 	// 1. Delete orphaned files (will cascade delete file_chunks)
 	// 2. Delete orphaned blobs (will cascade delete blob_chunks for deleted blobs)