fix(coding-agent): avoid SSH ControlMaster on Windows

packages/coding-agent/test/ssh/connection-manager.test.ts

@@ -1,14 +1,15 @@
 import { describe, expect, it } from "bun:test";
-import { buildRemoteCommand } from "../../src/ssh/connection-manager";
+import { buildRemoteCommand, supportsSshControlMaster } from "../../src/ssh/connection-manager";
 
 describe("buildRemoteCommand", () => {
-	it("includes -n to bind stdin to /dev/null for mux channel opens", async () => {
+	it("includes -n and OpenSSH ControlMaster options on Unix-like platforms", async () => {
 		const args = await buildRemoteCommand(
 			{
 				name: "host",
 				host: "192.168.3.146",
 			},
 			"ls -la",
+			{ platform: "linux" },
 		);
 
 		expect(args[0]).toBe("-n");
@@ -16,4 +17,34 @@ describe("buildRemoteCommand", () => {
 		expect(args.at(-2)).toBe("192.168.3.146");
 		expect(args.at(-1)).toBe("ls -la");
 	});
+
+	it("omits OpenSSH ControlMaster options on Windows", async () => {
+		const args = await buildRemoteCommand(
+			{
+				name: "host",
+				host: "192.168.3.146",
+			},
+			"ls -la",
+			{ platform: "win32" },
+		);
+
+		expect(args[0]).toBe("-n");
+		expect(args).not.toContain("ControlMaster=auto");
+		expect(args.some(arg => arg.startsWith("ControlPath="))).toBe(false);
+		expect(args).not.toContain("ControlPersist=3600");
+		expect(args).toContain("BatchMode=yes");
+		expect(args.at(-2)).toBe("192.168.3.146");
+		expect(args.at(-1)).toBe("ls -la");
+	});
+});
+
+describe("supportsSshControlMaster", () => {
+	it("disables OpenSSH connection multiplexing on native Windows", () => {
+		expect(supportsSshControlMaster("win32")).toBe(false);
+	});
+
+	it("keeps OpenSSH connection multiplexing on Unix-like platforms", () => {
+		expect(supportsSshControlMaster("linux")).toBe(true);
+		expect(supportsSshControlMaster("darwin")).toBe(true);
+	});
 });