Implement clipboard and QR presentation

docs/configuration.md

@@ -26,6 +26,9 @@ key_material = "keys"
 # accepted and split without launching a shell.
 editor = ["code", "--wait"]
 
+# Optional; upstream pass defaults to 45 seconds. Values are limited to 1..300.
+clipboard_timeout_seconds = 45
+
 [[git.remotes]]
 name = "origin"
 url = "https://git.example.test/alice/password-store.git"
@@ -49,6 +52,12 @@ store; duplicate names and duplicate reference pairs are errors.
 The HTTPS account name is stored inside the protected credential record, not in
 TOML. OpenPGP passphrases are addressed by the resolved primary fingerprint.
 
+`clipboard_timeout_seconds` controls the native clipboard presentation lease.
+It defaults to 45 seconds for upstream `pass` compatibility and must be between
+1 and 300 seconds. The CLI remains alive for the lease so Linux can serve its
+selection and every platform can restore or clear the value reliably without a
+background helper process.
+
 Passwords, passphrases, tokens, credentials, private keys, and other secret
 values are forbidden in TOML. Unknown fields are rejected. Parse errors never
 echo the source line or value, so an accidentally supplied secret is not