Beta server and role come from the dashboard

The owner sets them on the admin page; the bot polls the shared beta_settings
row (30s) and moves the beta commands if the server changes. BETA_* env vars
are gone.

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

schema.sql

@@ -73,6 +73,17 @@ CREATE TABLE IF NOT EXISTS meeting_settings (
     lobby_channel_id BIGINT
 );
 
+-- Who counts as a beta tester: holders of role_id in guild_id. One row, set by
+-- the owner on the dashboard's admin page (the API creates and writes it, see
+-- its migration 000021); the bot only reads it.
+CREATE TABLE IF NOT EXISTS beta_settings (
+    id BOOLEAN PRIMARY KEY DEFAULT TRUE CHECK (id),
+    guild_id BIGINT,
+    role_id BIGINT,
+    updated_by BIGINT,
+    updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
 -- A server can have several lobbies (at most 10; the trigger enforces it, and
 -- is the same as the API's migration 000020). meeting_settings.lobby_channel_id
 -- is the old single-lobby column, no longer read.