sketch: exclude internal processes (headless-chrome) from port monitoring

Add SKETCH_IGNORE_PORTS environment variable to headless-shell browser processes
and modify port monitoring to exclude processes with this variable.

Co-Authored-By: sketch <hello@sketch.dev>
Change-ID: sff3b145df27ee3bek
diff --git a/claudetool/browse/browse.go b/claudetool/browse/browse.go
index 928860d..e96a7f9 100644
--- a/claudetool/browse/browse.go
+++ b/claudetool/browse/browse.go
@@ -80,6 +80,8 @@
 		opts = append(opts, chromedp.Flag("--disable-dbus", true))
 		// This can be pretty slow in tests
 		opts = append(opts, chromedp.WSURLReadTimeout(60*time.Second))
+		// Add environment variable to mark this as a sketch internal process
+		opts = append(opts, chromedp.Env("SKETCH_IGNORE_PORTS=1"))
 		allocCtx, _ := chromedp.NewExecAllocator(b.ctx, opts...)
 		browserCtx, browserCancel := chromedp.NewContext(
 			allocCtx,