fix: only the owner decides who hosts a group, and nobody is made a member unasked

- hub: a node may host a group only if its account owns it or the owner
  approved that node (new `group_hosts`). Membership was the ceiling, and
  every member holds the group key, so any member's node could register as a
  host and be the one clients kept. A node claiming a group it may not host
  is recorded as a request; the owner is notified once and approves or
  refuses it (GET/POST/DELETE /v1/groups/{id}/hosts[/{node_id}]), which
  takes effect on a connected node at once.
- hub: an owner adding a username creates an invitation (new
  `group_invitations`), accepted or declined by the invitee
  (/v1/groups/invitations, /{id}/invitation/accept|decline). Until then the
  group is not listed, not dialled, not searched and not in any token.
  Invitation links, open joins and group creation still make members
  directly: they are the account's own act.
- hub: the MNP token names only the group it is minted for (group_id is now
  required), so a node operator no longer learns a member's other groups.
- SPA: invitations on the home page; invited people and host requests in
  the group's settings; the transport sends group_id. Ten catalogues.
- Browser probes for both screens, run in Chrome and Firefox.
- Design §5.2, §7.2, §7.3, AV32, AV33; protocol §6.3; user guide.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/api/invite_links.py b/packages/meshbay-hub/src/meshbay_hub/api/invite_links.py
index 3c50e19..86fbbb4 100644
--- a/packages/meshbay-hub/src/meshbay_hub/api/invite_links.py
+++ b/packages/meshbay-hub/src/meshbay_hub/api/invite_links.py
@@ -30,7 +30,7 @@ from meshbay_hub import mail
 from meshbay_hub.api.deps import _decode_token, get_current_user, require_user_scope
 from meshbay_hub.api.middleware import limiter
 from meshbay_hub.db.engine import get_db
-from meshbay_hub.db.models import Group, GroupInviteLink, GroupMember, User
+from meshbay_hub.db.models import Group, GroupInvitation, GroupInviteLink, GroupMember, User
 
 router = APIRouter(prefix="/v1/groups", tags=["invite-links"])
 redeem_router = APIRouter(prefix="/v1/invite-links", tags=["invite-links"])
@@ -322,6 +322,11 @@ async def redeem_invite_link(
             raise HTTPException(status_code=404, detail="invite_not_valid")
         if not await db.get(GroupMember, (group.id, current_user.id)):
             db.add(GroupMember(group_id=group.id, user_id=current_user.id))
+        # Redeeming a link is the invitee's own act, so it answers an
+        # invitation to the same group as well.
+        pending = await db.get(GroupInvitation, (group.id, current_user.id))
+        if pending is not None:
+            await db.delete(pending)
         from meshbay_hub.api.notifications import create_notification
         await create_notification(
             db, row.created_by, "invite_link_redeemed",