Migrate CLI E2E tests to Node.js 26

Run the CLI subprocess suites and benchmark tools as native TypeScript with
node:test, and move them under test/e2e-cli.

Update CI and Compose runners, run local smoke tests on Linux, macOS, and
Windows, and collect source-mapped CLI coverage with c8.

test/e2e-cli/test-p2p-relay-disconnect.ts

@@ -0,0 +1,29 @@
+import { test } from "node:test";
+import process from "node:process";
+import { fileURLToPath } from "node:url";
+import { runProcess } from "./helpers/process.ts";
+import assert from "node:assert/strict";
+
+test("p2p lifecycle: explicit disconnect closes and pauses relay WebSockets", async () => {
+    const result = await runProcess(process.execPath, {
+        args: [fileURLToPath(new URL("./relay-disconnect-probe.mjs", import.meta.url))],
+        env: {
+            RELAY: process.env["RELAY"] ?? "ws://nostr-relay:7777/",
+            RELAY_TIMEOUT_MS: process.env["LIVESYNC_P2P_RELAY_READY_TIMEOUT_MS"] ?? "15000",
+        },
+        stdout: "piped",
+        stderr: "piped",
+    });
+    const stdout = new TextDecoder().decode(result.stdout).trim();
+    const stderr = new TextDecoder().decode(result.stderr).trim();
+
+    assert(result.success, `Relay disconnect probe failed\nstdout: ${stdout}\nstderr: ${stderr}`);
+    const report = JSON.parse(stdout.split("\n").at(-1) ?? "{}") as {
+        socketsClosed?: number;
+        stayedDisconnectedWhilePaused?: boolean;
+        reconnectedAfterResume?: boolean;
+    };
+    assert((report.socketsClosed ?? 0) > 0, "The probe did not observe an open relay WebSocket");
+    assert.deepStrictEqual(report.stayedDisconnectedWhilePaused, true);
+    assert.deepStrictEqual(report.reconnectedAfterResume, true);
+});