feat: Implement major features and fix theming bug

This commit introduces several new features and a critical bug fix.

- Implemented a full "Quick Pay" flow for both within and outside the bank, including IFSC validation, beneficiary verification, and a TPIN-based payment process.
- Added a date range filter to the Account Statement screen and streamlined the UI by removing the amount filters.
- Fixed a major bug that prevented dynamic theme changes from being applied. The app now correctly switches between color themes.
- Refactored and improved beneficiary management, transaction models, and the fund transfer flow to support NEFT/RTGS.

lib/data/models/ifsc.dart

@@ -1,16 +1,16 @@
-class ifsc {
+class Ifsc {
   final String ifscCode;
   final String bankName;
   final String branchName;
 
-  ifsc({
+  Ifsc({
     required this.ifscCode,
     required this.bankName,
     required this.branchName,
   });
 
-  factory ifsc.fromJson(Map<String, dynamic> json) {
-    return ifsc(
+  factory Ifsc.fromJson(Map<String, dynamic> json) {
+    return Ifsc(
       ifscCode: json['ifsc_code'] ?? '',
       bankName: json['bank_name'] ?? '',
       branchName: json['branch_name'] ?? '',
@@ -29,4 +29,5 @@ class ifsc {
   String toString() {
     return 'IFSC(ifscCode: $ifscCode, bankName: $bankName, branchName: $branchName)';
   }
-}
+}
+