Add business spans and silence the frontend health poll

Manual INTERNAL spans for the business steps the auto-instrumentation
can't name: fraud.score_transaction, sanctions.lookup_watchlist,
ledger.settle and insights.aggregate_120d, with ledgerline.* attributes
(account, amount, risk score, match outcome). holder_name stays off the
spans. Each span starts after its handler's chaos flag reads and
injection points, and no chaos-derived values become attributes.

The gateway's /api/health/all fan-out now runs under
suppress_instrumentation: with the route excluded, its five downstream
/healthz calls were each a parentless root trace.

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 import trace
 from opentelemetry.instrumentation.fastapi import FastAPIInstrumentor
 from opentelemetry.instrumentation.sqlalchemy import SQLAlchemyInstrumentor
 
@@ -15,6 +16,7 @@ from .repository import is_match
 
 SERVICE_NAME = "sanctions"
 logger = configure_logging(SERVICE_NAME)
+tracer = trace.get_tracer(__name__)
 setup_telemetry(service_name=SERVICE_NAME)
 app = FastAPI(title=SERVICE_NAME)
 
@@ -66,7 +68,12 @@ async def lookup(body: LookupRequest):
         logger.info(f"slow_sanctions chaos sleeping {delay:.3f}s for request_id={body.request_id}")
         await asyncio.sleep(delay)
 
-    match = await is_match(body.holder_name)
+    # holder_name is PII: it stays off the span; only the outcome is recorded.
+    with tracer.start_as_current_span("sanctions.lookup_watchlist") as span:
+        match = await is_match(body.holder_name)
+        span.set_attribute("ledgerline.sanctions.matched", match is not None)
+        if match:
+            span.set_attribute("ledgerline.sanctions.list_source", match["list_source"])
     if match:
         return {"matched": True, **match}
     return {"matched": False, "country": None, "list_source": None}