Per mara's review: drop the #hive:<server> room alias (special chars) and
rediscover the canonical Space by its hardcoded plain name instead.
ensure_hive_space dedup is now:
1. room-id file present -> reuse it
2. else scan the admin's joined rooms for the m.space named HIVE_SPACE_NAME
('hive') and adopt the first match (re-persisting the file) -> recovers
the existing space after a state wipe instead of creating a duplicate
3. else createRoom (plain name, no alias)
find_space_by_name walks /joined_rooms and checks each room's m.room.create
type == m.space and m.room.name == 'hive'. No alias, no special-char anchor.
server_name is no longer needed by ensure_hive_space (dropped the param).
d043b1ed4e