Release 3.8.1.1: lighter idle UI poll, core cache, multicore ping.

Reduce idle CPU (cheap PollUI, binary cache, logbuf cap, DOM fingerprint),
speed ping/AWG HostPort, CopyBuffer pool; ship arm64 build and update notes.

Co-authored-by: Cursor <cursoragent@cursor.com>

server/update.json

@@ -1,6 +1,6 @@
 {
-  "version": "3.8.0",
-  "notes": "Navis 3.8.0+3: UDP ping Hy2/AWG (soft-ok без ложных «недоступен»); Mac .app zip update; EnsureCore lock; getState без секретов.",
+  "version": "3.8.1",
+  "notes": "Navis 3.8.1+1: меньше нагрузки в простое (лёгкий опрос UI, кэш ядер, список серверов не мигает); быстрее пинг; стабильнее логи и AWG-прокси; параллельная работа на нескольких ядрах CPU.",
   "platform": "windows-amd64",
   "os": "windows",
   "arch": "amd64",
@@ -16,13 +16,13 @@
     },
     "darwin-arm64": {
       "url": "https://git.evilfox.cc/test2/navi/raw/branch/main/dist/navis-release/darwin-arm64/Navis",
-      "sha256": "bd507de6f434f53f95954c8e411cc1f8bb526d5b5353b1242de5bc9fb673670f",
+      "sha256": "42e90ef84c1000b0850e89b30e13b2c15b0ca230a3ede28038fa03b3b493ec2e",
       "os": "darwin",
       "arch": "arm64",
       "dmg_url": "https://git.evilfox.cc/test2/navi/raw/branch/main/dist/navis-release/darwin-arm64/Navis.dmg",
       "zip_url": "https://git.evilfox.cc/test2/navi/raw/branch/main/dist/navis-release/darwin-arm64/Navis.app.zip",
-      "zip_sha256": "2aaac597f7246c67fc825cd11f49d2b4fc0fa6bd9b89a1b1e4290e6a96c01de4",
-      "dmg_sha256": "26ddacc3b3bc372aa4833336e60fb32862fb30ee555a8a6e460811f45f9f5cee"
+      "zip_sha256": "e8e95be506542bc1d2cbf259bbddd9f40967d7ef9bf8ac1c9b8d44ddd83f8c05",
+      "dmg_sha256": "8ba9a6b18c594800445a344f6955a750f3dd208181e612f07e26330dd1a25fc2"
     },
     "darwin-amd64": {
       "url": "https://git.evilfox.cc/test2/navi/raw/branch/main/dist/navis-release/darwin-amd64/Navis",