Silence prune and snapshot removal status under --cron and --quiet (closes #294)

PruneBlobs, CleanupLocalSnapshots, RemoveSnapshot, RemoveAllSnapshots
and snapshot purge wrote their status lines straight to stdout, so
`snapshot create --cron --prune` printed on every successful run and
--quiet did not silence `prune`, `snapshot purge`, `snapshot remove` or
`remote nuke`. Those lines now go through internal/ui, which drops them
under --cron and --quiet; warnings, errors and --json documents still
print.

The confirmation prompts still write straight to stdout, as the
`database delete` prompt does, together with what they ask to delete:
the snapshot list before the purge prompt, and the blob count and size
before the prune prompt. With --force those lines are status lines.

The two purge test fixtures gained the UI writer production always sets.

Model: opus-5-5

internal/vaultik/snapshot.go

@@ -574,7 +574,7 @@ func (v *Vaultik) PurgeSnapshotsWithOptions(opts *SnapshotPurgeOptions) error {
 
 	if len(toDelete) == 0 {
 		if !opts.Quiet {
-			v.printlnStdout("No snapshots to delete")
+			v.UI.Infof("No snapshots to delete.")
 		}
 
 		return nil
@@ -631,19 +631,19 @@ func selectSnapshotsToPurge(
 func (v *Vaultik) confirmAndExecutePurge(
 	toDelete []SnapshotInfo, force, quiet bool,
 ) error {
-	if !quiet {
+	// Confirm unless --force is used. The list, the prompt and its answer
+	// bypass the UI: they are an interactive exchange the operator must
+	// see, so --quiet does not silence them.
+	if !force {
 		v.stdoutf("The following snapshots will be deleted:\n\n")
 
 		for _, snap := range toDelete {
 			v.stdoutf("  %s (%s, %s)\n",
 				snap.ID,
-				snap.Timestamp.Format("2006-01-02 15:04:05"),
+				snap.Timestamp.Format(time.DateTime),
 				ubytes(snap.CompressedSize))
 		}
-	}
 
-	// Confirm unless --force is used
-	if !force {
 		v.stdoutf("\nDelete %d snapshot(s)? [y/N] ", len(toDelete))
 
 		var confirm string
@@ -661,7 +661,16 @@ func (v *Vaultik) confirmAndExecutePurge(
 			return nil
 		}
 	} else if !quiet {
-		v.stdoutf("\nDeleting %d snapshot(s) (--force specified)\n", len(toDelete))
+		v.UI.Infof("The following snapshots will be deleted:")
+
+		for _, snap := range toDelete {
+			v.UI.Detailf("%s (%s, %s)",
+				v.UI.Snapshot(snap.ID.String()),
+				snap.Timestamp.Format(time.DateTime),
+				ubytes(snap.CompressedSize))
+		}
+
+		v.UI.Infof("Deleting %d snapshot(s) (--force specified).", len(toDelete))
 	}
 
 	// Delete snapshots (both local and remote)
@@ -694,9 +703,9 @@ func (v *Vaultik) confirmAndExecutePurge(
 	}
 
 	if !quiet {
-		v.stdoutf("Deleted %d snapshot(s)\n", len(toDelete))
-		v.printlnStdout(
-			"\nNote: Run 'vaultik prune' to clean up unreferenced remote blobs.")
+		v.UI.Infof("Deleted %d snapshot(s).", len(toDelete))
+		v.UI.Noticef("Run '%s' to clean up unreferenced remote blobs.",
+			pruneCommandHint)
 	}
 
 	return nil
@@ -1069,7 +1078,7 @@ func (v *Vaultik) CleanupLocalSnapshots(opts *PruneOptions) error {
 			log.Info("Removing stale local snapshot record", "snapshot_id", id)
 
 			if !opts.JSON {
-				v.stdoutf("Removing stale local record: %s\n", id)
+				v.UI.Infof("Removing stale local record: %s.", v.UI.Snapshot(id))
 			}
 
 			err = v.deleteSnapshotFromLocalDB(id)
@@ -1092,9 +1101,9 @@ func (v *Vaultik) CleanupLocalSnapshots(opts *PruneOptions) error {
 	}
 
 	if removed == 0 {
-		v.printlnStdout("No stale local snapshots found.")
+		v.UI.Infof("No stale local snapshots found.")
 	} else {
-		v.stdoutf("Removed %d stale local snapshot record(s).\n", removed)
+		v.UI.Infof("Removed %d stale local snapshot record(s).", removed)
 	}
 
 	return nil
@@ -1273,14 +1282,15 @@ func (v *Vaultik) RemoveSnapshot(
 	}
 
 	if inLocalIndex {
-		v.stdoutf("Removed snapshot '%s' from local database\n", snapshotID)
+		v.UI.Infof("Removed snapshot '%s' from local database.",
+			v.UI.Snapshot(snapshotID))
 	}
 
 	if result.RemoteRemoved {
-		v.printlnStdout("Removed snapshot metadata from remote storage")
-		v.stdoutf("\nNote: The removed snapshot's blobs remain on the remote. "+
+		v.UI.Infof("Removed snapshot metadata from remote storage.")
+		v.UI.Noticef("The removed snapshot's blobs remain on the remote. "+
 			"Run '%s' to delete any blobs no longer referenced by any "+
-			"remaining remote snapshot.\n", pruneCommandHint)
+			"remaining remote snapshot.", pruneCommandHint)
 	}
 
 	return result, nil
@@ -1336,21 +1346,23 @@ func (v *Vaultik) removeSnapshotDryRun(
 		return result, v.outputRemoveJSON(result)
 	}
 
-	v.stdoutf("Would remove snapshot: %s\n", snapshotID)
+	v.UI.Infof("Would remove snapshot: %s.", v.UI.Snapshot(snapshotID))
 
 	if !opts.LocalOnly {
-		v.printlnStdout("Would also remove snapshot metadata from " +
-			"remote storage (blobs untouched)")
+		v.UI.Infof("Would also remove snapshot metadata from " +
+			"remote storage (blobs untouched).")
 	}
 
-	v.printlnStdout("[Dry run - no changes made]")
+	v.UI.Noticef("Dry run: no changes made.")
 
 	return result, nil
 }
 
 // confirmRemoveSnapshot prompts for confirmation before removing a
 // snapshot. Returns false (treating EOF/read errors as "no") unless the
-// user answers "y".
+// user answers "y". The prompt and its answer bypass the UI: they are an
+// interactive exchange the operator must see, so --quiet does not
+// silence them.
 func (v *Vaultik) confirmRemoveSnapshot(snapshotID string, opts *RemoveOptions) bool {
 	if opts.LocalOnly {
 		v.stdoutf("Remove snapshot '%s' from local database "+
@@ -1456,7 +1468,7 @@ func (v *Vaultik) RemoveAllSnapshots(opts *RemoveOptions) (*RemoveResult, error)
 
 	if len(localSnaps) == 0 && len(orphanRemoteKeys) == 0 {
 		if !opts.JSON {
-			v.printlnStdout("No snapshots found")
+			v.UI.Infof("No snapshots found.")
 		}
 
 		return &RemoveResult{}, nil
@@ -1561,27 +1573,27 @@ func (v *Vaultik) handleRemoveAllDryRun(
 	}
 
 	if !opts.JSON {
-		v.stdoutf("Would remove %d local snapshot(s):\n", len(localSnaps))
+		v.UI.Infof("Would remove %d local snapshot(s):", len(localSnaps))
 
 		for _, id := range localSnaps {
-			v.stdoutf("  %s\n", id)
+			v.UI.Detailf("%s", v.UI.Snapshot(id))
 		}
 
 		if !opts.LocalOnly {
 			if len(orphanRemoteKeys) > 0 {
-				v.stdoutf("Would also remove %d orphan remote snapshot key(s):\n",
+				v.UI.Infof("Would also remove %d orphan remote snapshot key(s):",
 					len(orphanRemoteKeys))
 
 				for _, key := range orphanRemoteKeys {
-					v.stdoutf("  %s\n", key)
+					v.UI.Detailf("%s", key)
 				}
 			} else {
-				v.printlnStdout("Would also remove snapshot metadata from " +
-					"remote storage (blobs untouched)")
+				v.UI.Infof("Would also remove snapshot metadata from " +
+					"remote storage (blobs untouched).")
 			}
 		}
 
-		v.printlnStdout("[Dry run - no changes made]")
+		v.UI.Noticef("Dry run: no changes made.")
 	}
 
 	if opts.JSON {
@@ -1630,10 +1642,10 @@ func (v *Vaultik) executeRemoveAll(
 		return result, v.outputRemoveJSON(result)
 	}
 
-	v.stdoutf("Removed %d snapshot(s)\n", len(result.SnapshotsRemoved))
+	v.UI.Infof("Removed %d snapshot(s).", len(result.SnapshotsRemoved))
 
 	if !opts.LocalOnly && result.RemoteRemoved {
-		v.printlnStdout("Removed snapshot metadata from remote storage")
+		v.UI.Infof("Removed snapshot metadata from remote storage.")
 	}
 
 	return result, nil