feat(stripe_js): add Stripe.js bindings for US bank account collection and microdeposit verification

Add JS interop extensions and freezed data classes for four Stripe.js v3
methods that were previously missing from the stripe_js package:

- collectBankAccountForPayment / collectBankAccountForSetup
- verifyMicrodepositsForPayment / verifyMicrodepositsForSetup

These methods enable the Financial Connections authentication flow for
US bank account (ACH) payments and setup intents on the web platform.

Each method takes a single options object containing the clientSecret
and params/data, matching the Stripe.js API contract.

Author: BiAksoy

packages/stripe_js/lib/src/api/payment_intents/collect_bank_account_for_payment_params.dart

@@ -0,0 +1,36 @@
+import 'package:freezed_annotation/freezed_annotation.dart';
+import 'package:stripe_js/stripe_api.dart';
+
+part 'collect_bank_account_for_payment_params.freezed.dart';
+part 'collect_bank_account_for_payment_params.g.dart';
+
+@freezed
+abstract class CollectBankAccountForPaymentParams
+    with _$CollectBankAccountForPaymentParams {
+  const factory CollectBankAccountForPaymentParams({
+    /// The type of payment method to collect. Currently only
+    /// `us_bank_account` is supported.
+    @JsonKey(name: 'payment_method_type') required String paymentMethodType,
+
+    /// Payment method data to prefill, including billing details.
+    @JsonKey(name: 'payment_method_data')
+    CollectBankAccountForPaymentMethodData? paymentMethodData,
+  }) = _CollectBankAccountForPaymentParams;
+
+  factory CollectBankAccountForPaymentParams.fromJson(
+    Map<String, dynamic> json,
+  ) => _$CollectBankAccountForPaymentParamsFromJson(json);
+}
+
+@freezed
+abstract class CollectBankAccountForPaymentMethodData
+    with _$CollectBankAccountForPaymentMethodData {
+  const factory CollectBankAccountForPaymentMethodData({
+    /// Billing details for the payment method.
+    @JsonKey(name: 'billing_details') BillingDetails? billingDetails,
+  }) = _CollectBankAccountForPaymentMethodData;
+
+  factory CollectBankAccountForPaymentMethodData.fromJson(
+    Map<String, dynamic> json,
+  ) => _$CollectBankAccountForPaymentMethodDataFromJson(json);
+}