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/cli/snapshot.go

@@ -24,6 +24,8 @@ func NewSnapshotCommand() *cobra.Command {
 	cmd.AddCommand(newSnapshotListCommand())
 	cmd.AddCommand(newSnapshotPurgeCommand())
 	cmd.AddCommand(newSnapshotVerifyCommand())
+	cmd.AddCommand(newSnapshotRemoveCommand())
+	cmd.AddCommand(newSnapshotPruneCommand())
 
 	return cmd
 }
@@ -281,3 +283,123 @@ func newSnapshotVerifyCommand() *cobra.Command {
 
 	return cmd
 }
+
+// newSnapshotRemoveCommand creates the 'snapshot remove' subcommand
+func newSnapshotRemoveCommand() *cobra.Command {
+	opts := &vaultik.RemoveOptions{}
+
+	cmd := &cobra.Command{
+		Use:     "remove <snapshot-id>",
+		Aliases: []string{"rm"},
+		Short:   "Remove a snapshot and its orphaned blobs",
+		Long: `Removes a snapshot and any blobs that are no longer referenced by other snapshots.
+
+This command downloads manifests from all other snapshots to determine which blobs
+are still in use, then deletes any blobs that would become orphaned.`,
+		Args: cobra.ExactArgs(1),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			snapshotID := args[0]
+
+			// Use unified config resolution
+			configPath, err := ResolveConfigPath()
+			if err != nil {
+				return err
+			}
+
+			rootFlags := GetRootFlags()
+			return RunWithApp(cmd.Context(), AppOptions{
+				ConfigPath: configPath,
+				LogOptions: log.LogOptions{
+					Verbose: rootFlags.Verbose,
+					Debug:   rootFlags.Debug,
+				},
+				Modules: []fx.Option{},
+				Invokes: []fx.Option{
+					fx.Invoke(func(v *vaultik.Vaultik, lc fx.Lifecycle) {
+						lc.Append(fx.Hook{
+							OnStart: func(ctx context.Context) error {
+								go func() {
+									if _, err := v.RemoveSnapshot(snapshotID, opts); err != nil {
+										if err != context.Canceled {
+											log.Error("Failed to remove snapshot", "error", err)
+											os.Exit(1)
+										}
+									}
+									if err := v.Shutdowner.Shutdown(); err != nil {
+										log.Error("Failed to shutdown", "error", err)
+									}
+								}()
+								return nil
+							},
+							OnStop: func(ctx context.Context) error {
+								v.Cancel()
+								return nil
+							},
+						})
+					}),
+				},
+			})
+		},
+	}
+
+	cmd.Flags().BoolVarP(&opts.Force, "force", "f", false, "Skip confirmation prompt")
+	cmd.Flags().BoolVar(&opts.DryRun, "dry-run", false, "Show what would be deleted without deleting")
+
+	return cmd
+}
+
+// newSnapshotPruneCommand creates the 'snapshot prune' subcommand
+func newSnapshotPruneCommand() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "prune",
+		Short: "Remove orphaned data from local database",
+		Long: `Removes orphaned files, chunks, and blobs from the local database.
+
+This cleans up data that is no longer referenced by any snapshot, which can
+accumulate from incomplete backups or deleted snapshots.`,
+		Args: cobra.NoArgs,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			// Use unified config resolution
+			configPath, err := ResolveConfigPath()
+			if err != nil {
+				return err
+			}
+
+			rootFlags := GetRootFlags()
+			return RunWithApp(cmd.Context(), AppOptions{
+				ConfigPath: configPath,
+				LogOptions: log.LogOptions{
+					Verbose: rootFlags.Verbose,
+					Debug:   rootFlags.Debug,
+				},
+				Modules: []fx.Option{},
+				Invokes: []fx.Option{
+					fx.Invoke(func(v *vaultik.Vaultik, lc fx.Lifecycle) {
+						lc.Append(fx.Hook{
+							OnStart: func(ctx context.Context) error {
+								go func() {
+									if _, err := v.PruneDatabase(); err != nil {
+										if err != context.Canceled {
+											log.Error("Failed to prune database", "error", err)
+											os.Exit(1)
+										}
+									}
+									if err := v.Shutdowner.Shutdown(); err != nil {
+										log.Error("Failed to shutdown", "error", err)
+									}
+								}()
+								return nil
+							},
+							OnStop: func(ctx context.Context) error {
+								v.Cancel()
+								return nil
+							},
+						})
+					}),
+				},
+			})
+		},
+	}
+
+	return cmd
+}