Native Validation DSL

v1.27.0 — ValidatorRuleBuilderExtensions adds 19 named, fluent methods on ValidatorRuleBuilder<T>. Property names are inferred automatically from Expression<Func<T, TProperty>> for clear default error messages — no raw predicates needed:

// Before — verbose, raw predicates, manual error messages
var validator = new ValidatorRuleBuilder<CreateUserRequest>()
    .Rule(u => u.Name, "NotEmpty", "Name is required", v => !string.IsNullOrEmpty(v))
    .Rule(u => u.Name, "MaxLength", "Name is too long", v => v.Length <= 100)
    .Rule(u => u.Email, "Email", "Invalid email", v => emailRegex.IsMatch(v))
    .Rule(u => u.Age, "Range", "Age must be 18–120", v => v >= 18 && v <= 120)
    .Build();

// After — native DSL, field names auto-inferred in default messages
var validator = new ValidatorRuleBuilder<CreateUserRequest>()
    .NotEmpty(u => u.Name)                    // "'Name' must not be empty."
    .MaxLength(u => u.Name, 100)              // "'Name' must not exceed 100 characters."
    .EmailAddress(u => u.Email)               // "'Email' must be a valid email address."
    .Range(u => u.Age, 18, 120)              // "'Age' must be between 18 and 120."
    .Build();

Category	Rules
String	NotEmpty, NotWhiteSpace, MinLength, MaxLength, Length, EmailAddress, Matches, StartsWith, EndsWith, Contains
Numeric (IComparable<TNum>)	GreaterThan, LessThan, Range, Positive, NonNegative
Collection	NotEmpty<TItem>, MinCount, MaxCount
Reference	NotNull

All numeric rules are generic — work with int, long, double, decimal, and any IComparable<TNum>.

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