Implement clipboard and QR presentation

docs/read-domains.md

@@ -23,6 +23,9 @@ number. Storage selects that line directly from decrypted bytes and returns a
 `PresentationSecret` containing the logical entry, line, channel, and redacted
 zeroizing contents. The adapter never parses rendered terminal output, and a
 missing or empty requested line is an explicit failure.
+The resulting secret is consumed by the shared presentation service documented
+in [`presentation.md`](presentation.md); plaintext is not written to CLI output
+for clipboard or QR requests.
 
 ## Name and plaintext search