Learn's PayloadEnvelope moves unchanged into halkyon_app, so that Train
seals its rows with the same envelope; Learn imports it from there. It
gets tests of its own: a payload sealed for its table, row, column and
item opens there alone, a changed one or one under a key not open never
does, and a readable one is trusted only signed by the account where it
was signed for.
Learn's app tests haven't run with the move (its build needs clang,
missing on this machine); analysis passes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
