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/run-ci-suite.ts

@@ -0,0 +1,21 @@
+import { spawnProcess } from "./helpers/process.ts";
+import { fileURLToPath } from "node:url";
+import TASKS from "./ci-tasks.json" with { type: "json" };
+
+for (const [index, task] of TASKS.entries()) {
+    console.log(`\n[CLI E2E ${index + 1}/${TASKS.length}] ${task}`);
+    const child = spawnProcess(process.execPath, {
+        args: [fileURLToPath(new URL("./run-task.ts", import.meta.url)), task],
+        cwd: import.meta.dirname,
+        stdin: "inherit",
+        stdout: "inherit",
+        stderr: "inherit",
+    });
+    const status = await child.status;
+    if (!status.success) {
+        console.error(`[CLI E2E] ${task} failed with exit code ${status.code}.`);
+        process.exit(status.code);
+    }
+}
+
+console.log(`\n[CLI E2E] CI suite passed (${TASKS.length} tasks).`);