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>

internal/update/update.go

@@ -18,11 +18,11 @@ import (
 
 // CurrentVersion is the product/semver used for update eligibility (feed "version").
 // Keep major.minor.patch only — no build suffix here.
-const CurrentVersion = "3.8.0"
+const CurrentVersion = "3.8.1"
 
 // BuildNumber is the monotonic build within CurrentVersion (Windows FileVersion 4th part,
 // macOS CFBundleVersion suffix, Android versionCode low digits). Bump on every release build.
-const BuildNumber = 3
+const BuildNumber = 1
 
 // DefaultManifestURL is the update feed (hosted in the project git repo).
 const DefaultManifestURL = "https://git.evilfox.cc/test2/navi/raw/branch/main/dist/update.json"