feat: align SDK with updated OpenAPI spec and add missing unit tests

- Update generated types from new openapi.yaml (capsule stats, usage,
  metrics, pause/resume lifecycle, host/channel management, auth flow)
- Add Capsule pause/resume/ping/getMetrics lifecycle methods
- Add Capsule.waitForReady abort signal support
- Add PtyManager.connect and PtySession disposal
- Fix HttpClient empty-body response handling (content-length: 0)
- Add streamProcess() to CommandManager for background process streams
- Add integration tests for capsule lifecycle, git, and PTY features
- Add unit tests for AsyncQueue error paths, PtySession.close,
  Git.checkout without create, Git.add single string,
  Notebook.execCell error case, and PtyStartOptions fields

tests/git.test.ts

@@ -71,4 +71,36 @@ describe("Git", () => {
 			"At least one file is required",
 		);
 	});
+
+	it("checks out an existing branch without creating it", async () => {
+		const capsule = new Capsule("cap_1", {
+			baseUrl: "https://api.example.com",
+		});
+		const exec = vi.spyOn(capsule.commands, "exec").mockResolvedValue({
+			exit_code: 0,
+			stdout: "",
+		});
+
+		await capsule.git.checkout("main");
+
+		expect(exec).toHaveBeenCalledWith("git", {
+			args: ["checkout", "main"],
+		});
+	});
+
+	it("normalizes a single string file argument in add", async () => {
+		const capsule = new Capsule("cap_1", {
+			baseUrl: "https://api.example.com",
+		});
+		const exec = vi.spyOn(capsule.commands, "exec").mockResolvedValue({
+			exit_code: 0,
+			stdout: "",
+		});
+
+		await capsule.git.add("src/a.ts");
+
+		expect(exec).toHaveBeenCalledWith("git", {
+			args: ["add", "src/a.ts"],
+		});
+	});
 });