fix: restore missing function parameter in validateAndNormalizeInputs method

- Add missing $function parameter to validateAndNormalizeInputs() method signature
- Fix all calls to pass appropriate function name (bcadd, bcsub, bcmul, etc.)
- Resolves TypeError: validateNumberString() argument #2 must be string, null given
- Fixes CI test failures caused by rector auto-refactoring removing required parameter

All 193 tests passing with 496 assertions

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

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

Author: nanasess

src/BCMath.php

@@ -58,7 +58,7 @@ abstract class BCMath
      *
      * @throws \ValueError if inputs are not well-formed
      */
-    protected static function validateAndNormalizeInputs(string $num1, string $num2): array
+    protected static function validateAndNormalizeInputs(string $num1, string $num2, string $function): array
     {
         self::validateNumberString($num1, $function, 1, 'num1');
         self::validateNumberString($num2, $function, 2, 'num2');
@@ -398,7 +398,7 @@ public static function isNegative(BigInteger $x): bool
     public static function add(string $num1, string $num2, ?int $scale = null): string
     {
         // Phase 1: Argument validation
-        [$num1, $num2] = self::validateAndNormalizeInputs($num1, $num2);
+        [$num1, $num2] = self::validateAndNormalizeInputs($num1, $num2, 'bcadd');
 
         // Phase 2: Scale resolution and validation
         $scale = self::resolveScale($scale);
@@ -420,7 +420,7 @@ public static function add(string $num1, string $num2, ?int $scale = null): stri
     public static function sub(string $num1, string $num2, ?int $scale = null): string
     {
         // Phase 1: Argument validation
-        [$num1, $num2] = self::validateAndNormalizeInputs($num1, $num2);
+        [$num1, $num2] = self::validateAndNormalizeInputs($num1, $num2, 'bcsub');
 
         // Phase 2: Scale resolution and validation
         $scale = self::resolveScale($scale);
@@ -442,7 +442,7 @@ public static function sub(string $num1, string $num2, ?int $scale = null): stri
     public static function mul(string $num1, string $num2, ?int $scale = null): string
     {
         // Phase 1: Argument validation
-        [$num1, $num2] = self::validateAndNormalizeInputs($num1, $num2);
+        [$num1, $num2] = self::validateAndNormalizeInputs($num1, $num2, 'bcmul');
 
         // Phase 2: Scale resolution and validation
         $scale = self::resolveScale($scale);
@@ -473,7 +473,7 @@ public static function mul(string $num1, string $num2, ?int $scale = null): stri
     public static function div(string $num1, string $num2, ?int $scale = null): string
     {
         // Phase 1: Argument validation
-        [$num1, $num2] = self::validateAndNormalizeInputs($num1, $num2);
+        [$num1, $num2] = self::validateAndNormalizeInputs($num1, $num2, 'bcdiv');
 
         // Phase 2: Scale resolution and validation
         $scale = self::resolveScale($scale);
@@ -504,7 +504,7 @@ public static function div(string $num1, string $num2, ?int $scale = null): stri
     public static function mod(string $num1, string $num2, ?int $scale = null): string
     {
         // Phase 1: Argument validation
-        [$num1, $num2] = self::validateAndNormalizeInputs($num1, $num2);
+        [$num1, $num2] = self::validateAndNormalizeInputs($num1, $num2, 'bcmod');
 
         // Phase 2: Scale resolution and validation
         $scale = self::resolveScale($scale);
@@ -529,7 +529,7 @@ public static function mod(string $num1, string $num2, ?int $scale = null): stri
     public static function comp(string $num1, string $num2, ?int $scale = null): int
     {
         // Phase 1: Argument validation
-        [$num1, $num2] = self::validateAndNormalizeInputs($num1, $num2);
+        [$num1, $num2] = self::validateAndNormalizeInputs($num1, $num2, 'bccomp');
 
         // Phase 2: Scale resolution and validation
         $scale = self::resolveScaleForComparison($scale);