fix: aggregate national fleet by province

tests/test_app.mjs

@@ -0,0 +1,41 @@
+import assert from 'node:assert/strict';
+import fs from 'node:fs';
+import vm from 'node:vm';
+
+const source = fs.readFileSync(new URL('../app.js', import.meta.url), 'utf8');
+const checks = `
+dashboard = {
+  vehicles: [
+    { vin: 'VIN-GD-1', plateNumber: '粤A00001', online: true, dailyMileageKm: 10, locationAvailable: true, longitude: 113.2, latitude: 23.1 },
+    { vin: 'VIN-GD-2', plateNumber: '粤B00002', online: false, dailyMileageKm: 5, locationAvailable: false },
+    { vin: 'VIN-ZJ-1', plateNumber: '浙F00003', online: true, dailyMileageKm: 8, locationAvailable: true, longitude: 120.7, latitude: 30.7 },
+    { vin: 'VIN-X-1', plateNumber: '观光车001', online: false, dailyMileageKm: 0, locationAvailable: false }
+  ]
+};
+const summary = buildVehicleProvinceNodes();
+assert.equal(summary.nodes.length, 2);
+assert.equal(summary.unassigned, 1);
+const guangdong = summary.nodes.find(node => node.nameZh === '广东');
+assert.equal(guangdong.count, 2);
+assert.equal(guangdong.online, 1);
+assert.equal(guangdong.dist, 15);
+
+map = { getZoom: () => 4.8 };
+assert.equal(vehicleNodes().length, 2);
+assert.ok(vehicleNodes().every(node => node.kind === 'vehicleProvince'));
+
+map = { getZoom: () => 8 };
+assert.ok(vehicleNodes().every(node => node.kind === 'vehicleCluster'));
+assert.equal(vehicleNodes().reduce((sum, node) => sum + node.count, 0), 2);
+`;
+
+const sandbox = {
+  assert,
+  console,
+  document: { addEventListener() {} },
+  window: {},
+  setInterval() {},
+  clearInterval() {}
+};
+vm.runInNewContext(`${source}\n${checks}`, sandbox, { filename: 'app.js' });
+console.log('vehicle province aggregation tests: ok');