refactor: extract config warning log formatter

src/core/services/config-warning-runtime-service.test.ts

@@ -0,0 +1,34 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+import {
+  formatConfigWarningRuntimeService,
+  logConfigWarningRuntimeService,
+} from "./config-warning-runtime-service";
+
+test("formatConfigWarningRuntimeService formats warning line", () => {
+  const message = formatConfigWarningRuntimeService({
+    path: "ankiConnect.enabled",
+    value: "oops",
+    fallback: true,
+    message: "invalid type",
+  });
+  assert.equal(
+    message,
+    '[config] ankiConnect.enabled: invalid type value="oops" fallback=true',
+  );
+});
+
+test("logConfigWarningRuntimeService delegates to logger", () => {
+  const logs: string[] = [];
+  logConfigWarningRuntimeService(
+    {
+      path: "x.y",
+      value: 1,
+      fallback: 2,
+      message: "bad",
+    },
+    (line) => logs.push(line),
+  );
+  assert.equal(logs.length, 1);
+  assert.match(logs[0], /^\[config\] x\.y: bad /);
+});