`tauri signer sign` emits .sig files that are base64-wrapped minisign
documents — the same wrapping already handled for the pinned public key —
but verifySignatureReader fed the wrapped text straight to
minisign.Signature.UnmarshalText, so every real release signature failed to
parse ("minisign: invalid signature"). Unwrap base64 when the text is not a
raw minisign document; raw documents (and the test fixtures) pass through
unchanged.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
