feat(inbox): migrate CRM Inbox to @insignia/iios-messaging-ui SDK

Replace the bespoke in-CRM inbox with the SDK's <Inbox>, driven by a new
CrmInboxAdapter over the be-crm data door (crm.inbox.* + crm.mail.*).
Demo mode falls back to the SDK MockInboxAdapter. Maps --miu-* tokens for
.miu-inbox to the CRM theme.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/components/dashboard/dashboard.tsx

@@ -16,7 +16,7 @@ import { Rules } from "./rules";
 import { AiAssistant } from "./ai-assistant";
 import { TeamManagement } from "./team-management";
 import { MessengerSdk } from "./messenger-sdk";
-import { Inbox } from "./inbox";
+import { InboxSdk } from "./inbox-sdk";
 import "../../app/dashboard/dashboard.css";
 
 export function Dashboard() {
@@ -48,7 +48,7 @@ export function Dashboard() {
               : active === "rules" ? <Rules />
               : active === "ai" ? <AiAssistant />
               : active === "messenger" ? <MessengerSdk />
-              : active === "inbox" ? <Inbox />
+              : active === "inbox" ? <InboxSdk />
               : active === "team" ? <TeamManagement />
               : <ComingSoon title={title} icon={item?.icon ?? "dashboard"} onGo={setActive} />}
           </ToastProvider>