docs: add schedule for Node.js 25 and Node.js 26 (#1095)

Author: aduh95

schedule.json

@@ -137,5 +137,17 @@
     "maintenance": "2026-10-20",
     "end": "2028-04-30",
     "codename": ""
+  },
+  "v25": {
+    "start": "2025-10-15",
+    "maintenance": "2026-04-01",
+    "end": "2026-06-01"
+  },
+  "v26": {
+    "start": "2026-04-22",
+    "lts": "2026-10-28",
+    "maintenance": "2027-10-20",
+    "end": "2029-04-30",
+    "codename": ""
   }
 }