fix(types): correct FormData iterator return types to include File

`FormData.values()` and `FormData.entries()` incorrectly typed their
return values as `string` instead of `FormDataEntryValue` (string | File),
inconsistent with `get()`, `getAll()`, and `forEach()` in the same interface.

Closes #27194

Co-Authored-By: Claude <noreply@anthropic.com>

packages/bun-types/globals.d.ts

@@ -1680,8 +1680,8 @@ interface FormData {
   set(name: string, blobValue: Blob, filename?: string): void;
   forEach(callbackfn: (value: Bun.FormDataEntryValue, key: string, parent: FormData) => void, thisArg?: any): void;
   keys(): IterableIterator<string>;
-  values(): IterableIterator<string>;
-  entries(): IterableIterator<[string, string]>;
+  values(): IterableIterator<Bun.FormDataEntryValue>;
+  entries(): IterableIterator<[string, Bun.FormDataEntryValue]>;
 }
 declare var FormData: Bun.__internal.UseLibDomIfAvailable<"FormData", { prototype: FormData; new (): FormData }>;
 

test/regression/issue/27194.test.ts

@@ -0,0 +1,26 @@
+import { expect, test } from "bun:test";
+
+test("FormData.values() returns File objects, not just strings", () => {
+  const fd = new FormData();
+  const file = new File(["content"], "test.txt", { type: "text/plain" });
+  fd.append("textField", "hello");
+  fd.append("fileField", file);
+
+  const values = [...fd.values()];
+  expect(values).toHaveLength(2);
+  expect(values[0]).toBe("hello");
+  expect(values[1]).toBeInstanceOf(File);
+});
+
+test("FormData.entries() returns File objects in value position", () => {
+  const fd = new FormData();
+  const file = new File(["content"], "test.txt", { type: "text/plain" });
+  fd.append("textField", "hello");
+  fd.append("fileField", file);
+
+  const entries = [...fd.entries()];
+  expect(entries).toHaveLength(2);
+  expect(entries[0]).toEqual(["textField", "hello"]);
+  expect(entries[1][0]).toBe("fileField");
+  expect(entries[1][1]).toBeInstanceOf(File);
+});