feat(messenger): CRM consumes @insignia/iios-messaging-ui instead of embedding

The messenger tab now renders the shared SDK's <Messenger>, not the bespoke
in-CRM implementation. The CRM only supplies transport + theme:

- CrmMessagingAdapter implements the SDK's MessagingAdapter over the be-crm
  data door (crm.messenger.conversation.list/open, history, send, directory);
  live updates via a 4s poll for now (socket realtime is a follow-up that
  reuses messenger-socket.tsx). Tenancy/auth stay server-side.
- messenger-sdk.tsx wires MessagingProvider + adapter (live = CrmMessagingAdapter,
  demo = the SDK MockAdapter), themed by mapping --miu-* tokens to the CRM
  design system.
- dashboard renders <MessengerSdk/>; the old messenger.tsx is left in place
  for rollback and will be deleted once this is proven live.

NOTE: the SDK is installed from a local tarball (file:) for verification since
it isn't published yet. For deploy: publish @insignia/iios-messaging-ui to the
registry and change the dep to a version range. transpilePackages covers ESM.

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

package-lock.json

@@ -10,6 +10,7 @@
       "dependencies": {
         "@abe-kap/appshell-sdk": "^0.2.6",
         "@insignia/iios-kernel-client": "^0.1.4",
+        "@insignia/iios-messaging-ui": "file:../iios/packages/iios-messaging-ui/insignia-iios-messaging-ui-0.1.0.tgz",
         "clsx": "^2.1.1",
         "lucide-react": "^1.21.0",
         "next": "16.2.9",
@@ -1026,6 +1027,20 @@
         "socket.io-client": "^4.8.1"
       }
     },
+    "node_modules/@insignia/iios-messaging-ui": {
+      "version": "0.1.0",
+      "resolved": "file:../iios/packages/iios-messaging-ui/insignia-iios-messaging-ui-0.1.0.tgz",
+      "integrity": "sha512-6pSVWACjex1sXWzVqx+42rM6vgWEJ+1ud5y3DLKogJiQmfgFZgCB8vTw0PN/5FECugXC7iGuc9rV9RsHsP+EDw==",
+      "peerDependencies": {
+        "@insignia/iios-kernel-client": "*",
+        "react": ">=18"
+      },
+      "peerDependenciesMeta": {
+        "@insignia/iios-kernel-client": {
+          "optional": true
+        }
+      }
+    },
     "node_modules/@jridgewell/gen-mapping": {
       "version": "0.3.13",
       "resolved": "https://registry.npmjs.org/@jridgewell/gen-mapping/-/gen-mapping-0.3.13.tgz",