phase 4: drop stale gRPC nomenclature from integration tests

Phase 4 replaced the gateway's authenticated edge listener with a
Connect-Go HTTP/h2c bootstrap that natively serves Connect, gRPC,
and gRPC-Web. Sweep the integration suite so test names, comments,
and helper docs match the new transport posture: rename
TestUserAccount_GetThroughGatewayGRPC to TestUserAccount_GetThroughGatewayEdge,
flip "authenticated gRPC" / "signed gRPC" / "gateway gRPC" comments
to "authenticated edge", and align testenv doc strings.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

integration/user_settings_update_test.go

@@ -12,7 +12,7 @@ import (
 
 // TestUserSettingsUpdate verifies `user.settings.update` accepts a
 // valid BCP 47 / IANA pair and rejects malformed inputs through the
-// gateway gRPC surface.
+// gateway authenticated edge surface.
 func TestUserSettingsUpdate(t *testing.T) {
 	plat := testenv.Bootstrap(t, testenv.BootstrapOptions{})
 	ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)