test(api): add Bruno tests for analytics, books, and bulk operations

Analytics:
- Reading stats endpoint tests
- Device usage tests
- Popular books tests

Books:
- Bulk delete tests
- Bulk update tests

Collections:
- Bulk add books to collections tests

Conflicts:
- Bulk resolve conflicts tests
- Bulk dismiss conflicts tests
- Bulk resolve highest progress tests

All tests cover no user, user, and admin contexts

bruno/analytics/Get Device Usage.bru

@@ -0,0 +1,35 @@
+{
+  "meta": {
+    "name": "Get Device Usage",
+    "type": "http",
+    "event": [
+      {
+        "listen": "test",
+        "script": {
+          "exec": [
+            "// Test device usage response",
+            "if (response.status === 200) {",
+            "    tests['Device usage loaded'] = true;",
+            "    const body = JSON.parse(response.body);",
+            "    tests['Has devices array'] = Array.isArray(body.devices);",
+            "    if (body.devices.length > 0) {",
+            "        tests['Device has device_name'] = body.devices[0].device_name !== undefined;",
+            "        tests['Device has device_type'] = body.devices[0].device_type !== undefined;",
+            "        tests['Device has sync_count'] = body.devices[0].sync_count !== undefined;",
+            "    }",
+            "} else {",
+            "    tests['Device usage failed'] = false;",
+            "}"
+          ]
+        }
+      }
+    ]
+  },
+  "req": {
+    "url": "{{baseUrl}}/api/analytics/device-usage",
+    "method": "GET",
+    "headers": {
+      "Authorization": "Bearer {{authToken}}"
+    }
+  }
+}