Pure-Go assembly of the WinDivert filter clause. Empty PID list →
"false" (captures nothing — used during Discord-not-running window).
Non-IPv4 upstream → 0.0.0.0 fallback (caller should validate; the
builder degrades gracefully rather than panicking).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds github.com/imgk/divert-go v0.1.0 dependency. Embedded driver
binaries land at runtime in %PROGRAMDATA%\Drover\windivert\ via the
installer (next task).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>