fix(plugins): expose channel CLI metadata in discovery (#71309)

Merged via squash.

Prepared head SHA: ce6bb35812
Co-authored-by: gumadeiras <5599352+gumadeiras@users.noreply.github.com>
Co-authored-by: gumadeiras <5599352+gumadeiras@users.noreply.github.com>
Reviewed-by: @gumadeiras

extensions/matrix/index.test.ts

@@ -69,6 +69,37 @@ describe("matrix plugin", () => {
     expect(entry.setChannelRuntime).toEqual(expect.any(Function));
   });
 
+  it("registers CLI metadata during discovery registration", () => {
+    const registerChannel = vi.fn();
+    const registerCli = vi.fn();
+    const registerGatewayMethod = vi.fn();
+    const api = createTestPluginApi({
+      id: "matrix",
+      name: "Matrix",
+      source: "test",
+      config: {},
+      runtime: {} as never,
+      registrationMode: "discovery",
+      registerChannel,
+      registerCli,
+      registerGatewayMethod,
+    });
+
+    entry.register(api);
+
+    expect(registerChannel).toHaveBeenCalledTimes(1);
+    expect(registerCli).toHaveBeenCalledWith(expect.any(Function), {
+      descriptors: [
+        {
+          name: "matrix",
+          description: "Manage Matrix accounts, verification, devices, and profile state",
+          hasSubcommands: true,
+        },
+      ],
+    });
+    expect(registerGatewayMethod).not.toHaveBeenCalled();
+  });
+
   it("registers subagent lifecycle hooks during full runtime registration", () => {
     const on = vi.fn();
     const registerGatewayMethod = vi.fn();