Initial Navis client with NaiveProxy, profiles, ping and git updates

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

internal/sysproxy/other.go

@@ -0,0 +1,11 @@
+//go:build !windows
+
+package sysproxy
+
+type stubController struct{}
+
+func newPlatform() Controller { return stubController{} }
+
+func (stubController) Enable(string) error { return ErrUnsupported }
+func (stubController) Disable() error      { return nil }
+func (stubController) Enabled() bool       { return false }