feat: add comprehensive string format validators

- Add url() validator for URL validation
- Add uuid() validator for UUID string validation
- Add ip() validator for IPv4/IPv6 address validation
- Add minLength(), maxLength(), length() for string length constraints
- Add pattern() validator for regex pattern matching
- Add datetime() and date() validators for date format validation
- All validators support custom error messages
- Enhanced StringValidator with complete format validation suite

BREAKING CHANGE: StringValidator now includes many new validation methods

Author: lemmon

src/Lemmon/StringValidator.php

@@ -22,4 +22,90 @@ protected function validateType(mixed $value, string $key): mixed
         }
         return $value;
     }
+
+    public function email(?string $message = null): static
+    {
+        return $this->addValidation(
+            fn ($value, $key = null, $input = null) => filter_var($value, FILTER_VALIDATE_EMAIL) !== false,
+            $message ?? 'Value must be a valid email address.'
+        );
+    }
+
+    public function url(?string $message = null): static
+    {
+        return $this->addValidation(
+            fn ($value, $key = null, $input = null) => filter_var($value, FILTER_VALIDATE_URL) !== false,
+            $message ?? 'Value must be a valid URL.'
+        );
+    }
+
+    public function uuid(?string $message = null): static
+    {
+        return $this->addValidation(
+            fn ($value, $key = null, $input = null) => preg_match('/^[0-9a-f]{8}-[0-9a-f]{4}-[1-5][0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i', $value) === 1,
+            $message ?? 'Value must be a valid UUID.'
+        );
+    }
+
+    public function ip(?string $message = null): static
+    {
+        return $this->addValidation(
+            fn ($value, $key = null, $input = null) => filter_var($value, FILTER_VALIDATE_IP) !== false,
+            $message ?? 'Value must be a valid IP address.'
+        );
+    }
+
+    public function minLength(int $min, ?string $message = null): static
+    {
+        return $this->addValidation(
+            fn ($value, $key = null, $input = null) => mb_strlen($value) >= $min,
+            $message ?? "Value must be at least {$min} characters long."
+        );
+    }
+
+    public function maxLength(int $max, ?string $message = null): static
+    {
+        return $this->addValidation(
+            fn ($value, $key = null, $input = null) => mb_strlen($value) <= $max,
+            $message ?? "Value must be at most {$max} characters long."
+        );
+    }
+
+    public function length(int $exact, ?string $message = null): static
+    {
+        return $this->addValidation(
+            fn ($value, $key = null, $input = null) => mb_strlen($value) === $exact,
+            $message ?? "Value must be exactly {$exact} characters long."
+        );
+    }
+
+    public function pattern(string $regex, ?string $message = null): static
+    {
+        return $this->addValidation(
+            fn ($value, $key = null, $input = null) => preg_match($regex, $value) === 1,
+            $message ?? 'Value does not match the required pattern.'
+        );
+    }
+
+    public function datetime(string $format = 'Y-m-d\TH:i:s', ?string $message = null): static
+    {
+        return $this->addValidation(
+            function ($value, $key = null, $input = null) use ($format) {
+                $date = \DateTime::createFromFormat($format, $value);
+                return $date !== false && $date->format($format) === $value;
+            },
+            $message ?? "Value must be a valid datetime in format '{$format}'."
+        );
+    }
+
+    public function date(string $format = 'Y-m-d', ?string $message = null): static
+    {
+        return $this->addValidation(
+            function ($value, $key = null, $input = null) use ($format) {
+                $date = \DateTime::createFromFormat($format, $value);
+                return $date !== false && $date->format($format) === $value;
+            },
+            $message ?? "Value must be a valid date in format '{$format}'."
+        );
+    }
 }