feat: add rDesign module metadata, collab presence-leave cleanup

- Register rDesign in folk-rapp MODULE_META and shell FAVICON_BADGE_MAP
- Handle explicit presence-leave messages for immediate peer cleanup

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/folk-rapp.ts

@@ -42,6 +42,7 @@ const MODULE_META: Record<string, { badge: string; color: string; name: string;
 	rmeets:      { badge: "rMe", color: "#6ee7b7", name: "rMeets",     icon: "📹" },
 	rschedule:   { badge: "rSc", color: "#93c5fd", name: "rSchedule",  icon: "⏰" },
 	rsocials:    { badge: "rSo", color: "#f9a8d4", name: "rSocials",   icon: "📱" },
+	rdesign:     { badge: "rDe", color: "#7c3aed", name: "rDesign",   icon: "🎨" },
 };
 
 const styles = css`

server/shell.ts

@@ -47,6 +47,7 @@ const FAVICON_BADGE_MAP: Record<string, { badge: string; color: string }> = {
 	rschedule: { badge: "r⏱", color: "#a5b4fc" },
 	crowdsurf: { badge: "r🏄", color: "#fde68a" },
 	rids:      { badge: "r🪪", color: "#6ee7b7" },
+	rdesign:   { badge: "r🎨", color: "#7c3aed" },
 	rstack:    { badge: "r✨", color: "#c4b5fd" },
 };
 

shared/components/rstack-collab-overlay.ts

@@ -210,6 +210,21 @@ export class RStackCollabOverlay extends HTMLElement {
 			this.#renderBadge();
 			if (this.#panelOpen) this.#renderPanel();
 		});
+
+		// Listen for explicit leave signals (immediate cleanup, no GC wait)
+		this.#unsubLeave = runtime.onCustomMessage('presence-leave', (msg: any) => {
+			const pid = msg.peerId;
+			if (!pid || pid === this.#localPeerId) return;
+			if (this.#peers.has(pid)) {
+				this.#peers.delete(pid);
+				this.#renderBadge();
+				if (!this.#badgeOnly) {
+					this.#renderCursors();
+					this.#renderFocusRings();
+				}
+				if (this.#panelOpen) this.#renderPanel();
+			}
+		});
 	}
 
 	#connectToDoc() {