Config.Validate now parses every age_recipients entry with
age.ParseX25519Recipient, so a bad recipient fails at config load instead
of deep in a backup after the snapshot row and tree walk. On failure the
error names the position (age_recipients[N]) and never the value: a
recipient string can itself be a secret key an operator pasted by mistake,
and age's own error quotes its input. An entry starting with
AGE-SECRET-KEY- (compared case-insensitively) gets a specific message.
The remaining parse sites (blobgen.NewWriter, crypto NewEncryptor and
UpdateRecipients), reachable by callers that skip config.Load, likewise
drop the value and age's wrapped error, naming only the position.
test/config.yaml's placeholder second recipient is replaced with a valid
X25519 key so it still loads.
Model: opus-4-8