✅ Reject a mismatched strict fallback

The factory-contract test now also covers a fallback whose return does not
fit the common return of the handler map — a `number` handler with a
`string` fallback — which `getMatcherW` accepts as `number | string`.

src/primitive.test.ts

@@ -307,6 +307,8 @@ test("getMatcher factory rejects patterns outside its contract", () => {
     });
     // @ts-expect-error a gap without a `_` fallback is not exhaustive
     factory({ a: () => 1 });
+    // @ts-expect-error a `string` fallback does not fit the `number` handler
+    factory({ a: () => 1 }, () => "x");
 });
 
 test("getMatcherW factory rejects patterns outside its contract", () => {