fix: Update nginx config to use dynamic DNS resolution

- Replace upstream blocks with resolver directive
- Use variables for backend addresses to avoid startup errors
- Simplify configuration with single server block
- Add health check endpoint

server/api/node_modules/pstree.remy/tests/fixtures/index.js

@@ -0,0 +1,13 @@
+const spawn = require('child_process').spawn;
+function run() {
+  spawn(
+    'sh',
+    ['-c', 'node -e "setInterval(() => console.log(`running`), 200)"'],
+    {
+      stdio: 'pipe',
+    }
+  );
+}
+
+var runCallCount = process.argv[2] || 1;
+for (var i = 0; i < runCallCount; i++) run();