fix(inbox): show Multica logo for system-actor notifications (#2479)

Notifications from system actors (e.g. GitHub PR closed) were rendering
with an "S" initials fallback. The avatar now shows the Multica icon
when actor_type === "system", matching the platform's brand.

Co-authored-by: multica-agent <github@multica.ai>

packages/core/types/inbox.ts

@@ -25,7 +25,7 @@ export interface InboxItem {
   workspace_id: string;
   recipient_type: "member" | "agent";
   recipient_id: string;
-  actor_type: "member" | "agent" | null;
+  actor_type: "member" | "agent" | "system" | null;
   actor_id: string | null;
   type: InboxItemType;
   severity: InboxSeverity;

packages/core/workspace/hooks.ts

@@ -22,6 +22,7 @@ export function useActorName() {
   const getActorName = (type: string, id: string) => {
     if (type === "member") return getMemberName(id);
     if (type === "agent") return getAgentName(id);
+    if (type === "system") return "Multica";
     return "System";
   };
 

packages/ui/components/common/actor-avatar.tsx

@@ -3,12 +3,14 @@
 import { useState, useEffect } from "react";
 import { Bot } from "lucide-react";
 import { cn } from "@multica/ui/lib/utils";
+import { MulticaIcon } from "./multica-icon";
 
 interface ActorAvatarProps {
   name: string;
   initials: string;
   avatarUrl?: string | null;
   isAgent?: boolean;
+  isSystem?: boolean;
   size?: number;
   className?: string;
 }
@@ -18,6 +20,7 @@ function ActorAvatar({
   initials,
   avatarUrl,
   isAgent,
+  isSystem,
   size = 20,
   className,
 }: ActorAvatarProps) {
@@ -46,6 +49,8 @@ function ActorAvatar({
           className="h-full w-full object-cover"
           onError={() => setImgError(true)}
         />
+      ) : isSystem ? (
+        <MulticaIcon noSpin style={{ width: size * 0.55, height: size * 0.55 }} />
       ) : isAgent ? (
         <Bot style={{ width: size * 0.55, height: size * 0.55 }} />
       ) : (

packages/views/common/actor-avatar.tsx

@@ -53,6 +53,7 @@ export function ActorAvatar({
       initials={getActorInitials(actorType, actorId)}
       avatarUrl={getActorAvatarUrl(actorType, actorId)}
       isAgent={actorType === "agent"}
+      isSystem={actorType === "system"}
       size={size}
       className={className}
     />