Restore accidentally removed files, a few additional import/calculation fixes

inventory-server/dashboard/klaviyo-server/routes/metrics.routes.js

@@ -0,0 +1,29 @@
+import express from 'express';
+import { MetricsService } from '../services/metrics.service.js';
+
+const router = express.Router();
+
+export function createMetricsRoutes(apiKey, apiRevision) {
+  const metricsService = new MetricsService(apiKey, apiRevision);
+
+  // Get all metrics
+  router.get('/', async (req, res) => {
+    try {
+      console.log('[Metrics Route] Fetching metrics');
+      const data = await metricsService.getMetrics();
+      console.log('[Metrics Route] Success:', {
+        count: data.data?.length || 0
+      });
+      res.json(data);
+    } catch (error) {
+      console.error('[Metrics Route] Error:', error);
+      res.status(500).json({ 
+        status: 'error', 
+        message: error.message,
+        details: error.response?.data || null
+      });
+    }
+  });
+
+  return router;
+}