fix(server): probe libc asynchronously before serving requests (#16335)

Linux runner qualification generated a full Node diagnostic report to read one libc version field. Reverse DNS on open sockets could stop the event loop for minutes.

Replace report generation with a one-time asynchronous getconf probe during module initialization. Bound it to one second and 1 KiB of output, cache the measured facts, and preserve unknown-libc failure behavior.

Verification: 149 focused tests, repository typecheck and build, full CI, and fresh Greptile 5/5 with no comments. A timed-out local heartbeat fixture passed when rerun alone.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

server/src/__tests__/dev-runner-native-binary.test.ts

@@ -2,7 +2,7 @@ import fs from "node:fs";
 import os from "node:os";
 import path from "node:path";
 import { afterEach, describe, expect, it, vi } from "vitest";
-import { localPaperclipRunnerSupported, resetLocalAgentRunnerTargetCacheForTests } from "../lib/agent-runner-platform.js";
+import { paperclipRunnerSupportsPlatform } from "@paperclipai/shared";
 
 import {
   paperclipRunnerBinaryNeedsBuild,
@@ -16,7 +16,6 @@ const initialArchitecture = Object.getOwnPropertyDescriptor(process, "arch")!;
 
 afterEach(() => {
   vi.restoreAllMocks();
-  resetLocalAgentRunnerTargetCacheForTests();
   Object.defineProperty(process, "platform", initialPlatform);
   Object.defineProperty(process, "arch", initialArchitecture);
   for (const root of tempRoots) {
@@ -66,8 +65,7 @@ describe("paperclip runner native dev prerequisite", () => {
   it.each(["x64", "arm64"].flatMap(architecture => [[undefined, false], ["2.38", false], ["2.39", true], ["3.0", true]].map(([glibcVersionRuntime, native]) => ({ architecture, glibcVersionRuntime, native }))))("uses the measured libc prerequisite on Linux $architecture/$glibcVersionRuntime when no native run or flag requires it", ({ architecture, glibcVersionRuntime, native }) => {
     Object.defineProperty(process, "platform", { ...initialPlatform, value: "linux" });
     Object.defineProperty(process, "arch", { ...initialArchitecture, value: architecture });
-    vi.spyOn(process.report, "getReport").mockReturnValue({ header: { glibcVersionRuntime } } as never);
-    const nativeRunnerRequired = localPaperclipRunnerSupported();
+    const nativeRunnerRequired = paperclipRunnerSupportsPlatform("codex_local", "linux", architecture, glibcVersionRuntime ? "glibc" : "unknown", glibcVersionRuntime as string | undefined);
     expect(nativeRunnerRequired).toBe(native);
     expect(paperclipRunnerBinaryNeedsBuild({ repoRoot: "/checkout/without/a/staged/binary", nativeRunnerRequired })).toBe(native);
   });