Picker: share PR #218's guild_name field and its no-fallback-after-unlink rule

A server an org explicitly unlinked (unlinked_at) must not fall back to the
default org in the picker either, or the founding org could stream into it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

drb-frontend/components/NodeDiscordRadio.tsx

@@ -134,8 +134,8 @@ function DiscordPicker({
             <legend className="text-xs text-ink-muted mb-2">Discord server</legend>
             {usable.length === 0 ? (
               <p className="text-xs text-ink-2 bg-raised border border-line rounded-lg px-3 py-2">
-                No Discord server is linked to your organization yet. Add the DRB bot to your server; a platform
-                admin then links it to your organization.
+                No Discord server is linked to your organization yet. Add the DRB bot to your Discord server and
+                link it to your organization; it shows up here once the bot reports its channels.
               </p>
             ) : (
               <div className="space-y-1.5">