fix(persian): scope narrow weekday formatter to fa locales

Author: gpbl

examples/PersianEn.test.tsx

@@ -17,3 +17,10 @@ test("should render 6 rows", () => {
   render(<PersianEn />);
   expect(screen.getAllByRole("row")).toHaveLength(6);
 });
+
+test("should render English short weekday labels", () => {
+  render(<PersianEn />);
+  expect(
+    screen.getByRole("columnheader", { name: "Thursday", hidden: true }),
+  ).toHaveTextContent("Th");
+});

src/persian.tsx

@@ -91,16 +91,21 @@ export function DayPicker(
     noonSafe,
     overrides: dateLibProp,
   });
+  const locale = localeProp ?? faIR;
+
   return (
     <DayPickerComponent
       {...restProps}
-      locale={localeProp ?? faIR}
+      locale={locale}
       numerals={numerals ?? "arabext"}
       dir={dir ?? "rtl"}
       dateLib={dateLib}
       formatters={{
-        formatWeekdayName: (date, _options, lib) =>
-          (lib ?? dateLib).format(date, "ccccc"),
+        formatWeekdayName: (date, _options, lib) => {
+          const activeLib = lib ?? dateLib;
+          const isPersian = activeLib.options.locale?.code?.startsWith("fa");
+          return activeLib.format(date, isPersian ? "ccccc" : "cccccc");
+        },
         ...props.formatters,
       }}
     />