v0.275.0: a backup's data and its version travel together (R-696, 07 §6.6, D4 option A); R-695, R-691, R-694

The unit's data files are stamped with the versions that wrote them; the capture keeps the
definition the data belongs to; a restore never starts data under another version's
definition (unit restores refuse a mismatch; the off-site restore writes the snapshot's
definition); every tier's time is its data's; the conversion-copy release needs a dump on
the new engine. File-browser sync single-flight + no empty kept folder (R-695); the kept
view joins the folder's owning group, language switch resyncs (R-691); a restore-generated
login is not shown as the password (R-694). Red-proofs in
felhom.eu/documentation/audits/version-travel-2026-09-26/.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS

controller/internal/stacks/update.go

@@ -1011,7 +1011,7 @@ func (m *Manager) verifyAndConclude(ctx context.Context, name, dir string, env [
 		}
 		m.removeUndoCopies(name, rest)
 		if keep != nil {
-			m.recordConversionCopy(name, dir, &ConversionCopy{Volume: keep.Volume, Copy: keep.Copy, At: m.now().UTC().Format(time.RFC3339), From: entry.Convert.From, To: entry.Convert.To})
+			m.recordConversionCopy(name, dir, &ConversionCopy{Volume: keep.Volume, Copy: keep.Copy, At: m.now().UTC().Format(time.RFC3339), From: entry.Convert.From, To: entry.Convert.To, Service: entry.Convert.Service})
 			m.logger.Printf("[INFO] [stacks] update %s: KEEPING the pre-conversion datadir copy %s (PostgreSQL %d) until a backup of the converted app is proven", name, keep.Copy, entry.Convert.From)
 		}
 		_ = os.RemoveAll(filepath.Join(dir, preUpdateConvertDir))