Send a room-scoped line by naming the room

A Bot's line to a friend's Bot that is only in a room with it was refused
with no_relationship: bot-social decides reach from the pair's grants, and
a room claim writes a status='room' relationship that findActiveRelationship
does not read (#866, bot-social #43/#50).

Both send paths now name the room on send_as_member when roomContextFor
finds one open room here that holds both Bots, so the server's room-scoped
grant is the reach the pair already holds. Room lines (via room/room-share)
and a local shared room (#864) name none: a local room has no id on the
server, and naming one only earns room_not_shared. A room-scoped refusal is
reported as the room's answer, never retried on another Bot of mine.

Author: Birfy

changelog.d/866-room-scoped-send.fixed.md

@@ -0,0 +1 @@
+A Bot that shares a room with a friend's Bot can now send it a line again. Both send paths name the room on `send_as_member` when the two Bots are in one room this home has not left, so Bot Social decides on the room-scoped reach the two already hold instead of answering that they are not friends. Lines sent outside a room, into a local room, and after leaving the room name no room, and a room-scoped refusal now reads as the room's own sentence ("that room is closed between these Bots now…", "the room no longer lets these Bots reach each other…") instead of "you are not friends with this Bot" ([#866](https://github.com/ThinkFlowLab/FlyBot/issues/866)).