feat: wire remote-desktop plugin into core and rename i18n keys

Repoints core consumers (dispatcher, collab, session-sharing, tab
utils) at the plugin, adds isTabTypeAvailable gating for rdp/vnc/
telnet, widens hostCapability to accept an array, and renames the
guacamole i18n namespace to remoteDesktop.

src/ui/features/collab/CollabGuestView.tsx

@@ -1,7 +1,7 @@
 import { useEffect, useRef, useState } from "react";
 import { useTranslation } from "react-i18next";
 import { AlertCircle, Eye, Presentation, Users } from "lucide-react";
-import { GuacamoleDisplay } from "@/features/guacamole/GuacamoleDisplay.tsx";
+import { GuacamoleDisplay } from "../../../../plugins/remote-desktop/frontend/GuacamoleDisplay.tsx";
 import {
   GuestTerminalView,
   type SessionParticipantInfo,