feat: raise market_api rate to 20/min, add global Polygon cap at 45/min, add rate-limit API + watchlist warning

tests/test_scheduler.py

@@ -13,7 +13,7 @@ from services.scheduler.app import (
 
 class TestGetCadenceForSource:
     def test_default_cadence_market_api(self):
-        assert get_cadence_for_source("market_api", None) == 60
+        assert get_cadence_for_source("market_api", None) == 300
 
     def test_default_cadence_news_api(self):
         assert get_cadence_for_source("news_api", {}) == 300
@@ -57,7 +57,7 @@ class TestIsSourceDue:
         assert not is_source_due("market_api", None, last, "completed", 0, None, self._now())
 
     def test_completed_past_cadence_is_due(self):
-        last = self._now() - timedelta(seconds=120)
+        last = self._now() - timedelta(seconds=400)
         assert is_source_due("market_api", None, last, "completed", 0, None, self._now())
 
     def test_running_not_due(self):