feat: broker-aware factory for reconcile/journal/health tools

eod_reconcile, backfill_journal and the admin health block were hardwired
to AlpacaPaperClient — on a BROKER=tradier stack they would silently
reconcile/report against the wrong broker. make_trading_client() honors
BROKER env with no silent cross-broker fallback (missing Tradier keys =>
skip with reason, never fall back to Alpaca). Admin UI shows the active
broker label; JSON key stays 'alpaca' for compatibility.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/test_broker_factory.py

@@ -0,0 +1,56 @@
+"""make_trading_client honors BROKER env with no silent cross-broker fallback."""
+
+import unittest
+from unittest.mock import patch
+
+from alpaca_paper.client import AlpacaPaperClient
+from tradier_broker.client import TradierClient
+from tradier_broker.factory import make_trading_client
+
+ALPACA = {"ALPACA_API_KEY": "k", "ALPACA_SECRET_KEY": "s"}
+TRADIER = {"TRADIER_ACCESS_TOKEN": "t", "TRADIER_ACCOUNT_ID": "a"}
+
+
+def _env(extra):
+    env = {"BROKER": "", "TRADIER_ACCESS_TOKEN": "", "TRADIER_ACCOUNT_ID": "",
+           "TRADIER_ENV": "", "ALPACA_API_KEY": "", "ALPACA_SECRET_KEY": "",
+           "APCA_API_KEY_ID": "", "APCA_API_SECRET_KEY": "",
+           "APCA_API_BASE_URL": ""}
+    env.update(extra)
+    return patch.dict("os.environ", env)
+
+
+class FactoryTests(unittest.TestCase):
+    def test_default_is_alpaca(self):
+        with _env(ALPACA):
+            client, label = make_trading_client()
+        self.assertIsInstance(client, AlpacaPaperClient)
+        self.assertEqual(label, "alpaca-paper")
+
+    def test_tradier_selected(self):
+        with _env({**ALPACA, **TRADIER, "BROKER": "tradier"}):
+            client, label = make_trading_client()
+        self.assertIsInstance(client, TradierClient)
+        self.assertEqual(label, "tradier-sandbox")
+        self.assertIsInstance(client.data_client, AlpacaPaperClient)
+
+    def test_tradier_live_label(self):
+        with _env({**ALPACA, **TRADIER, "BROKER": "tradier", "TRADIER_ENV": "live"}):
+            _, label = make_trading_client()
+        self.assertEqual(label, "tradier-LIVE")
+
+    def test_no_fallback_when_tradier_keys_missing(self):
+        with _env({**ALPACA, "BROKER": "tradier"}):
+            client, label = make_trading_client()
+        self.assertIsNone(client)
+        self.assertIn("TRADIER_ACCESS_TOKEN", label)
+
+    def test_no_alpaca_keys(self):
+        with _env({}):
+            client, label = make_trading_client()
+        self.assertIsNone(client)
+        self.assertEqual(label, "no Alpaca keys")
+
+
+if __name__ == "__main__":
+    unittest.main()