Add IBAN validation using iban.js library

Implemented optional IBAN validation for the account form profile:
- Installed iban.js package for robust IBAN validation
- Added Zod validation with IBAN.isValid() for format checking
- Normalizes IBAN (removes spaces, uppercase) before storage
- Validates country-specific formats and checksums
- Added validation error messages in English and Croatian

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

package-lock.json

@@ -13,6 +13,7 @@
         "@mui/icons-material": "^7.3.5",
         "@mui/material": "^7.3.5",
         "@tailwindcss/typography": "^0.5.10",
+        "@types/iban": "^0.0.35",
         "@types/node": "20.5.7",
         "@zxing/browser": "^0.1.4",
         "@zxing/library": "^0.20.0",
@@ -20,6 +21,7 @@
         "bcrypt": "^5.1.1",
         "clsx": "^2.0.0",
         "daisyui": "^4.5.0",
+        "iban": "^0.0.14",
         "is-ua-webview": "^1.1.2",
         "mongodb": "^6.3.0",
         "next": "^14.0.2",
@@ -1745,6 +1747,12 @@
         "@types/node": "*"
       }
     },
+    "node_modules/@types/iban": {
+      "version": "0.0.35",
+      "resolved": "https://registry.npmjs.org/@types/iban/-/iban-0.0.35.tgz",
+      "integrity": "sha512-BOsp/b0ypIBnZdp1R8aP3n4w7I0n6vcObXtD0OT91lVSdo+Bx4VL26tW3yx1Dr9I4D5H3A27IOZoMVAdVfG4FQ==",
+      "license": "MIT"
+    },
     "node_modules/@types/json-schema": {
       "version": "7.0.15",
       "resolved": "https://registry.npmjs.org/@types/json-schema/-/json-schema-7.0.15.tgz",
@@ -5013,6 +5021,12 @@
         "node": ">= 6"
       }
     },
+    "node_modules/iban": {
+      "version": "0.0.14",
+      "resolved": "https://registry.npmjs.org/iban/-/iban-0.0.14.tgz",
+      "integrity": "sha512-+rocNKk+Ga9m8Lr9fTMWd+87JnsBrucm0ZsIx5ROOarZlaDLmd+FKdbtvb0XyoBw9GAFOYG2GuLqoNB16d+p3w==",
+      "license": "MIT"
+    },
     "node_modules/ignore": {
       "version": "5.3.1",
       "resolved": "https://registry.npmjs.org/ignore/-/ignore-5.3.1.tgz",