Caddy's tracing directive, switched by WEB_TRACING so a server without a collector does not log
a failed export every few seconds. It continues an incoming traceparent (the page starts one per
tap, #190) and passes it to ipx, so a request is one trace from the browser through Caddy into
ipx, and Caddy's access log carries its traceID. Checked against Tempo with a probe container:
service.name and deployment.environment.name come from the OTEL_ variables, over OTLP/HTTP.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>