feat: move remote desktop (RDP/VNC/Telnet) into a first-party plugin

Relocates guacamole backend/frontend source and tests into
plugins/remote-desktop, following the ssh-terminal/docker pattern.

plugins/remote-desktop/frontend/guacamole-websocket-url.test.ts

@@ -0,0 +1,68 @@
+import { describe, expect, it } from "vitest";
+import { buildGuacamoleWebSocketBaseUrl } from "./guacamole-websocket-url.js";
+
+const httpsLocation = {
+  protocol: "https:",
+  host: "termix.example.com",
+} as Location;
+
+describe("buildGuacamoleWebSocketBaseUrl", () => {
+  it("uses the same origin guacamole websocket path in production web builds", () => {
+    expect(
+      buildGuacamoleWebSocketBaseUrl({
+        isDev: false,
+        isElectronApp: false,
+        isEmbeddedApp: false,
+        basePath: "",
+        location: httpsLocation,
+      }),
+    ).toBe("wss://termix.example.com/guacamole/websocket/");
+  });
+
+  it("preserves the runtime base path for proxied web deployments", () => {
+    expect(
+      buildGuacamoleWebSocketBaseUrl({
+        isDev: false,
+        isElectronApp: false,
+        isEmbeddedApp: false,
+        basePath: "/termix",
+        location: httpsLocation,
+      }),
+    ).toBe("wss://termix.example.com/termix/guacamole/websocket/");
+  });
+
+  it("keeps direct local websocket access for development and embedded electron", () => {
+    expect(
+      buildGuacamoleWebSocketBaseUrl({
+        isDev: true,
+        isElectronApp: false,
+        isEmbeddedApp: false,
+        basePath: "/termix",
+        location: httpsLocation,
+      }),
+    ).toBe("ws://localhost:30008");
+
+    expect(
+      buildGuacamoleWebSocketBaseUrl({
+        isDev: false,
+        isElectronApp: true,
+        isEmbeddedApp: true,
+        basePath: "/termix",
+        location: httpsLocation,
+      }),
+    ).toBe("ws://127.0.0.1:30008");
+  });
+
+  it("uses the configured remote server URL for electron remote mode", () => {
+    expect(
+      buildGuacamoleWebSocketBaseUrl({
+        isDev: false,
+        isElectronApp: true,
+        isEmbeddedApp: false,
+        configuredServerUrl: "https://termix.example.com/termix/",
+        basePath: "",
+        location: httpsLocation,
+      }),
+    ).toBe("wss://termix.example.com/termix/guacamole/websocket/");
+  });
+});