Add performance regression detection: indexes, timing middleware, benchmark script

Nightshift-Task: perf-regression
Nightshift-Ref: https://github.com/marcus/nightshift

server/src/middleware/timing.js

@@ -0,0 +1,21 @@
+'use strict';
+
+const SLOW_THRESHOLD_MS = 200;
+
+function timingMiddleware(req, res, next) {
+  const start = Date.now();
+
+  res.on('finish', () => {
+    const duration = Date.now() - start;
+    const msg = `${req.method} ${req.path} ${res.statusCode} ${duration}ms`;
+    if (duration >= SLOW_THRESHOLD_MS) {
+      console.warn(`[SLOW] ${msg}`);
+    } else {
+      console.log(`[timing] ${msg}`);
+    }
+  });
+
+  next();
+}
+
+module.exports = timingMiddleware;