ipx-directory traces, and ipx's trace follows its calls there (#213)

The exporter setup and the traceparent parser move from ipx into ipx_directory::otel, which ipx
already depends on, so both binaries share them. The directory makes a span a request, a child of
the caller's traceparent, and a trace a refresher round with a span a feed; ipx sends the current
span's traceparent on every call to the directory and wraps each share in a span. The dashboard's
Traces row and the prod-check skill cover all three services.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Cargo.lock

@@ -1835,8 +1835,6 @@ dependencies = [
  "jsonwebtoken",
  "librqbit",
  "opentelemetry",
- "opentelemetry-otlp",
- "opentelemetry_sdk",
  "opml",
  "percent-encoding",
  "quick-xml 0.42.0",
@@ -1864,6 +1862,9 @@ dependencies = [
  "axum",
  "clap",
  "ipx-feed",
+ "opentelemetry",
+ "opentelemetry-otlp",
+ "opentelemetry_sdk",
  "reqwest",
  "sea-orm",
  "serde",
@@ -1873,6 +1874,7 @@ dependencies = [
  "toml",
  "tower",
  "tracing",
+ "tracing-opentelemetry",
  "tracing-subscriber",
  "url",
 ]