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/locales/en.json

@@ -903,7 +903,7 @@
     "useSocks5ProxyDesc": "Route connection through a proxy server",
     "connectionOrigin": "Connection Origin",
     "connectionOriginDesc": "Where this host's connection originates from. Overrides the desktop app's global default.",
-    "connectionOriginGuacamoleNote": "RDP, VNC and Telnet use the remote server unless you pick \"This device\", which needs a guacd this machine can reach — set one in the guacd URL setting, or per host under guacd Proxy.",
+    "connectionOriginRemoteDesktopNote": "RDP, VNC and Telnet use the remote server unless you pick \"This device\", which needs a guacd this machine can reach — set one in the guacd URL setting, or per host under guacd Proxy.",
     "connectionOriginDefault": "Use default",
     "connectionOriginLocal": "This device (local network)",
     "connectionOriginRemote": "Remote server",
@@ -2050,7 +2050,7 @@
     "userShareBadge": "User: {{username}}",
     "loadSharesFailed": "Failed to load active shares"
   },
-  "guacamole": {
+  "remoteDesktop": {
     "connecting": "Connecting to {{type}} session...",
     "checkingGuacd": "Checking remote desktop service...",
     "requestingToken": "Requesting {{type}} connection token...",
@@ -3665,9 +3665,9 @@
     "metrics": "Metrics",
     "sec": "sec",
     "logLevel": "Log Level",
-    "enableGuacamole": "Enable Guacamole",
-    "enableGuacamoleDesc": "RDP/VNC remote desktop",
-    "enableGuacamoleDocsLink": "View docs",
+    "enableRemoteDesktop": "Enable Remote Desktop",
+    "enableRemoteDesktopDesc": "RDP/VNC remote desktop",
+    "enableRemoteDesktopDocsLink": "View docs",
     "guacdUrl": "guacd URL",
     "tailscaleApiKey": "Tailscale API Key",
     "tailscaleApiKeyDescription": "Used for device discovery in the host editor. Supports Tailscale (tskey-) and Headscale (hskey-) keys. Generate a key at tailscale.com/admin/settings/keys or from your Headscale instance.",
@@ -3821,9 +3821,9 @@
     "metricsHistoryRetention": "Metrics History Retention",
     "metricsHistoryRetentionRange": "1 to 90 days",
     "days": "days",
-    "guacamoleSaved": "Guacamole settings saved",
-    "guacamoleSaveFailed": "Failed to save Guacamole settings",
-    "guacamoleUpdateFailed": "Failed to update Guacamole setting",
+    "remoteDesktopSaved": "Remote Desktop settings saved",
+    "remoteDesktopSaveFailed": "Failed to save Remote Desktop settings",
+    "remoteDesktopUpdateFailed": "Failed to update Remote Desktop setting",
     "tailscaleSettingsSaved": "Tailscale settings saved",
     "tailscaleSettingsSaveFailed": "Failed to save Tailscale settings",
     "logLevelUpdateFailed": "Failed to update log level",