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]>

internal/bot/bot.go

@@ -27,6 +27,7 @@ type Bot struct {
 	DBHost             string
 	LavalinkHost       string
 	LavalinkPass       string
+	betaGuild          string // where beta commands are registered right now
 }
 
 func NewBot(token, appID, guildID, lavalinkHost, lavalinkPass string, cmds []*discordgo.ApplicationCommand, services *services.Services, musicRepo *musicrepo.Repo, dbHost string) (*Bot, error) {
@@ -114,8 +115,6 @@ func (b *Bot) Start() error {
 		b.registeredCommands = append(b.registeredCommands, created)
 	}
 
-	b.registerBetaCommands()
-
 	b.Session.AddHandler(commands.HandleInteraction)
 
 	b.Session.AddHandler(func(s *discordgo.Session, c *discordgo.ChannelDelete) {
@@ -203,12 +202,65 @@ func (b *Bot) Start() error {
 	return nil
 }
 
+// betaPollEvery is how often the bot looks for a change to the beta settings
+// made on the dashboard.
+const betaPollEvery = 30 * time.Second
+
+// WatchBeta keeps the bot's idea of who the beta testers are in step with the
+// settings the owner saves on the dashboard. When the beta server changes, the
+// beta commands move with it. If the settings can't be read, the last known
+// ones stay in force (and before the first read, beta stays locked).
+func (b *Bot) WatchBeta(ctx context.Context, load func(context.Context) (guildID, roleID string, err error)) {
+	sync := func() {
+		guildID, roleID, err := load(ctx)
+		if err != nil {
+			log.Printf("beta: cannot read settings, keeping the last ones: %v", err)
+			return
+		}
+		beta.Configure(guildID, roleID)
+		if now := beta.GuildID(); now != b.betaGuild {
+			b.registerBetaCommands(b.betaGuild, now)
+			b.betaGuild = now
+		}
+	}
+	sync()
+	go func() {
+		t := time.NewTicker(betaPollEvery)
+		defer t.Stop()
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case <-t.C:
+				sync()
+			}
+		}
+	}()
+}
+
 // registerBetaCommands puts the beta commands in the beta server, and only
 // there, so nobody else sees them. Commands this bot left there that are no
 // longer beta (or no longer exist) are removed. When the beta server is also
-// the bot's main server, its regular commands are kept.
-func (b *Bot) registerBetaCommands() {
-	guildID := beta.GuildID()
+// the bot's main server, its regular commands are kept. If the beta server
+// changed, the beta commands are taken out of the old one.
+func (b *Bot) registerBetaCommands(previous, guildID string) {
+	if previous != "" && previous != guildID {
+		isBeta := map[string]bool{}
+		for _, cmd := range commands.BetaCommands {
+			isBeta[cmd.Name] = true
+		}
+		if old, err := b.Session.ApplicationCommands(b.AppID, previous); err != nil {
+			log.Printf("beta: cannot list commands in the previous server: %v", err)
+		} else {
+			for _, cmd := range old {
+				if isBeta[cmd.Name] {
+					if err := b.Session.ApplicationCommandDelete(b.AppID, previous, cmd.ID); err != nil {
+						log.Printf("beta: cannot remove '%v' from the previous server: %v", cmd.Name, err)
+					}
+				}
+			}
+		}
+	}
 	if guildID == "" {
 		return
 	}