Propagate traces over HTTP and add Redis spans

setup_telemetry now instruments httpx and redis process-wide. Both patch
the client classes, so clients created at import time (gateway's
_proxy_client, common.redis_client) are covered too. httpx CLIENT spans
inject traceparent, so the downstream FastAPI SERVER spans join the
caller's trace. gateway and fraud get setup_telemetry, the FastAPI span,
and the OTLP auth header. All seven services now export traces.

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

common/telemetry.py

@@ -3,6 +3,8 @@ from opentelemetry.sdk.resources import SERVICE_NAME, Resource
 from opentelemetry.sdk.trace import TracerProvider
 from opentelemetry.sdk.trace.export import BatchSpanProcessor
 from opentelemetry.exporter.otlp.proto.http.trace_exporter import OTLPSpanExporter
+from opentelemetry.instrumentation.httpx import HTTPXClientInstrumentor
+from opentelemetry.instrumentation.redis import RedisInstrumentor
 
 
 def setup_telemetry(service_name: str):
@@ -11,3 +13,8 @@ def setup_telemetry(service_name: str):
     provider = TracerProvider(resource=resource)
     provider.add_span_processor(processor)
     trace.set_tracer_provider(provider)
+
+    # Process-wide patches on the client classes, so they also cover clients
+    # created at import time (gateway's _proxy_client, common.redis_client).
+    HTTPXClientInstrumentor().instrument()
+    RedisInstrumentor().instrument()