feat: ship host metrics as a first-party in-process plugin

plugins/host-metrics/backend/widgets/system-collector.ts

@@ -0,0 +1,69 @@
+import type { Client } from "ssh2";
+import {
+  execCommand,
+  execPowerShell,
+  type HostPlatform,
+} from "../../../../src/backend/hosts/metrics-shared/common-utils.js";
+
+async function collectWindowsSystemMetrics(client: Client): Promise<{
+  hostname: string | null;
+  kernel: string | null;
+  os: string | null;
+}> {
+  let hostname: string | null = null;
+  let kernel: string | null = null;
+  let os: string | null = null;
+
+  try {
+    const { stdout } = await execPowerShell(
+      client,
+      "$os=Get-CimInstance Win32_OperatingSystem; [PSCustomObject]@{hostname=$env:COMPUTERNAME; kernel=[System.Environment]::OSVersion.Version.ToString(); os=$os.Caption} | ConvertTo-Json -Compress",
+    );
+    const parsed = JSON.parse(stdout.trim());
+    hostname = parsed?.hostname ? String(parsed.hostname) : null;
+    kernel = parsed?.kernel ? String(parsed.kernel) : null;
+    os = parsed?.os ? String(parsed.os).trim() : null;
+  } catch {
+    // expected
+  }
+
+  return { hostname, kernel, os };
+}
+
+export async function collectSystemMetrics(
+  client: Client,
+  platform?: HostPlatform,
+): Promise<{
+  hostname: string | null;
+  kernel: string | null;
+  os: string | null;
+}> {
+  if (platform === "windows") {
+    return collectWindowsSystemMetrics(client);
+  }
+
+  let hostname: string | null = null;
+  let kernel: string | null = null;
+  let os: string | null = null;
+
+  try {
+    const hostnameOut = await execCommand(client, "hostname");
+    const kernelOut = await execCommand(client, "uname -r");
+    const osOut = await execCommand(
+      client,
+      "command -v sw_vers >/dev/null 2>&1 && echo \"$(sw_vers -productName) $(sw_vers -productVersion)\" || (cat /etc/os-release 2>/dev/null | grep '^PRETTY_NAME=' | cut -d'\"' -f2)",
+    );
+
+    hostname = hostnameOut.stdout.trim() || null;
+    kernel = kernelOut.stdout.trim() || null;
+    os = osOut.stdout.trim() || null;
+  } catch {
+    // expected
+  }
+
+  return {
+    hostname,
+    kernel,
+    os,
+  };
+}