Instrument sanctions' FastAPI app in code

FastAPIInstrumentor.instrument_app gives sanctions its SERVER span back,
skipping /healthz (the Docker healthcheck flooded Tempo search) and the
ASGI receive/send INTERNAL spans. Drop the OTEL_* env vars only the
zero-code configurator read, and the unused SERVICE_NAME.

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

services/sanctions/app.py

@@ -3,6 +3,7 @@ import asyncio
 from fastapi import FastAPI, Request
 from fastapi.responses import JSONResponse
 from pydantic import BaseModel
+from opentelemetry.instrumentation.fastapi import FastAPIInstrumentor
 
 from common.db import engine
 from common.logging_config import configure_logging
@@ -16,6 +17,11 @@ logger = configure_logging(SERVICE_NAME)
 setup_telemetry(service_name=SERVICE_NAME)
 app = FastAPI(title=SERVICE_NAME)
 
+FastAPIInstrumentor.instrument_app(
+    app,
+    excluded_urls="/healthz",
+    exclude_spans=["receive", "send"],
+)
 
 class LookupRequest(BaseModel):
     holder_name: str