feat(release): ship the Windows build as 3x-ui.exe with version info and icon

Kaspersky (Trojan.Win64.Agent.sb / .smhqgz) and Defender flag the
Windows build heuristically. A stripped, unsigned Go binary with no
VERSIONINFO, icon or manifest scores high on those heuristics, so the
release job now generates a resource .syso with go-winres from
winres/winres.json, stamped with internal/config/version, before
go build. The .syso is a build artifact and is gitignored.

The Windows zip now carries 3x-ui.exe instead of x-ui.exe, matching the
project name, and the executable embeds the 3X logo as its icon. The
icon is a square 256px crop of media/3x-ui-dark.png, since the source
logo is 400x200 and Windows icons must be square.

.gitignore

@@ -32,6 +32,7 @@ Thumbs.db
 
 # Ignore Go build files
 *.exe
+*.syso
 x-ui.db
 x-ui.db-shm
 x-ui.db-wal