Fix TestRoutingIntegration and improve DetectUserRole robustness

Amp-Thread-ID: https://ampcode.com/threads/T-fc47ce9d-88a4-4bcd-b9cb-79327d98dee7
Co-authored-by: Amp <amp@ampcode.com>

internal/beads/routing_integration_test.go

@@ -14,6 +14,10 @@ import (
 )
 
 func TestRoutingIntegration(t *testing.T) {
+	// Isolate from user's git config (e.g. url.insteadOf) to ensure deterministic URLs
+	t.Setenv("GIT_CONFIG_GLOBAL", "/dev/null")
+	t.Setenv("GIT_CONFIG_SYSTEM", "/dev/null")
+
 	tests := []struct {
 		name               string
 		setupGit           func(t *testing.T, dir string)