Hosted rooms: the hub's side

Rooms made on the website (hosted_room, migration 0005), the REST routes in
docs/hosted-rooms.md, and the realtime room.* protocol: joining with the
capacity, adult and linked-account rules, seats, numbered messages with
forged senders dropped and a rate limit, closing. The Rooms page lists them,
with a form to make one and the owner's edit and close.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

packages/db/drizzle/meta/_journal.json

@@ -36,6 +36,13 @@
       "when": 1793347080470,
       "tag": "0004_parent_info",
       "breakpoints": true
+    },
+    {
+      "idx": 5,
+      "version": "7",
+      "when": 1793355138984,
+      "tag": "0005_hosted_rooms",
+      "breakpoints": true
     }
   ]
 }