fix: add health checks and repair dashboard contracts

tests/test_server_reliability.py

@@ -21,6 +21,35 @@ def test_server_import_does_not_start_scheduler_threads(server):
     assert server._threads_started_during_import == []
 
 
+def test_frontend_uses_backtest_metric_values_contract(server):
+    assert ".filter(d => d.metric_values && d.metric_values[metricKey] != null)" in server.DASHBOARD_HTML
+    assert ".map(d => ({ date: d.date, value: d.metric_values[metricKey]" in server.DASHBOARD_HTML
+
+
+def test_dashboard_does_not_issue_duplicate_initial_backtest_request(server):
+    assert "const br = await fetch('/api/backtest');" not in server.DASHBOARD_HTML
+    assert server.DASHBOARD_HTML.count("fetch('/api/backtest?mode=' + currentMode)") == 1
+
+
+def test_health_endpoints_distinguish_process_liveness_from_data_readiness(server, monkeypatch):
+    assert server.health_live() == {"status": "ok"}
+
+    monkeypatch.setattr(server, "load_cache", lambda: {})
+    unavailable = server.health_ready()
+    assert unavailable.status_code == 503
+
+    monkeypatch.setattr(
+        server,
+        "load_cache",
+        lambda: {"_scored": {"composite_score": 72, "scored_count": 8}},
+    )
+    assert server.health_ready() == {
+        "status": "ready",
+        "score": 72,
+        "scored_metrics": 8,
+    }
+
+
 def test_server_cache_and_history_use_reliable_persistence(server, monkeypatch, tmp_path):
     monkeypatch.setattr(server, "CACHE_PATH", str(tmp_path / "cache.json"))
     monkeypatch.setattr(server, "HISTORY_PATH", str(tmp_path / "scores.jsonl"))