Ordered migration ladder applied on read, oldest step first.
Every step is a pure structural rewrite of one parsed envelope. 1.0 → 1.1
derives each backing's decoded length from its base64 length — arithmetic on
the encoded string, never a decode — and stamps the layout version that
envelope 1.0 left implicit.
Ordered migration ladder applied on read, oldest step first.
Every step is a pure structural rewrite of one parsed envelope.
1.0 → 1.1derives each backing's decoded length from its base64 length — arithmetic on the encoded string, never a decode — and stamps the layout version that envelope 1.0 left implicit.