Android half of ios#55, spec §6.24. An ordinary story envelope carrying
`gid`, fanned out to the members and recorded in the story set.
🔴 `Vault.groupStoryReach` returns the overlap rather than a warning: who
is excluded by this account's story audience and who is not a contact at
all, counted separately. The roster decides either way — those are two
different lists making two different statements and they will disagree —
so a disclosure that cannot name the consequence is not one.
🔴 The group label is adopted only from an actual member. The roster
check that guards group messages runs after the story branch, so without
this a sender could attach the id of a group they are not in and have
their story shown as having come from it. Dropped to null rather than
refusing the story: the story is legitimately theirs, and only the claim
about where it was posted is unverified.
The story branch already sat before group routing, which is what keeps a
group story out of the conversation — filed there it would be a story
that is a message, and one that never expires out of the thread. That
ordering is now written down rather than incidental.
⚠️ `gid` is persisted, or a reload forgets which story went where.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
