Refactor UI assets and harden quality checks

tests/test_store_metrics.py

@@ -0,0 +1,20 @@
+from karldns.store.metrics import _update_metric_increments
+
+
+def test_update_metric_increments_include_requested_outcomes() -> None:
+    increments = _update_metric_increments(
+        42.5,
+        is_success=True,
+        is_dns_failure=True,
+        is_reconcile_failure=False,
+        is_bad_ip=True,
+    )
+
+    assert increments == {
+        "update_requests_total": 1,
+        "update_latency_ms_total": 42.5,
+        "update_latency_samples_total": 1,
+        "update_success_total": 1,
+        "dns_failures_total": 1,
+        "bad_ip_total": 1,
+    }