fix: infer source fetch metrics

test/fetch-utils.test.mjs

@@ -1,6 +1,6 @@
 import test from 'node:test';
 import assert from 'node:assert/strict';
-import { safeFetch, safeFetchText, getFetchMetrics } from '../apis/utils/fetch.mjs';
+import { safeFetch, safeFetchText, getFetchMetrics, inferFetchSource } from '../apis/utils/fetch.mjs';
 
 test('safeFetch reports HTML as degraded JSON response', async () => {
   const originalFetch = globalThis.fetch;
@@ -34,3 +34,28 @@ test('safeFetchText returns text and byte count', async () => {
     globalThis.fetch = originalFetch;
   }
 });
+
+test('safeFetch attributes unlabelled requests to a stable provider source', async () => {
+  const originalFetch = globalThis.fetch;
+  globalThis.fetch = async () => ({
+    ok: true,
+    status: 200,
+    headers: { get: () => 'application/json' },
+    text: async () => '{"observations":[]}',
+  });
+  try {
+    const data = await safeFetch('https://api.fred.stlouisfed.org/fred/series/observations?series_id=VIXCLS', { retries: 0 });
+    assert.deepEqual(data, { observations: [] });
+    const bucket = getFetchMetrics().bySource.FRED;
+    assert.ok(bucket.requests >= 1);
+    assert.equal(bucket.lastStatus, 200);
+  } finally {
+    globalThis.fetch = originalFetch;
+  }
+});
+
+test('inferFetchSource returns provider names and host fallback', () => {
+  assert.equal(inferFetchSource('https://api.bls.gov/publicAPI/v2/timeseries/data/CPI'), 'BLS');
+  assert.equal(inferFetchSource('https://query1.finance.yahoo.com/v8/finance/chart/%5EGSPC'), 'YahooFinance');
+  assert.equal(inferFetchSource('https://unknown.example.test/path'), 'unknown.example.test');
+});