light-linq v1.3.0

• Add Enumerable order, orderDescending, asEnumerable, longCount,
  tryGetNonEnumeratedCount, cast, ofType, sequence and infiniteSequence.
• Support indexed callbacks in select, where, selectMany, skipWhile and
  takeWhile, including Queryable closure translation through IndexExpression.
• Add Enumerable selectMany and groupBy result selectors.
• Expand Queryable with append/prepend, reverse, default-if-empty, while/tail
  operations, key-based set operations, min/max-by, right joins, identity ordering,
  element access, count-by, aggregation and grouped aggregation.
• Add Queryable::asQueryable() and Enumerable::asQueryable() for deferred
  in-memory queries, preserving an existing IQueryable and its provider.
• Translate closures for Queryable ordering, grouping, aggregate selectors,
  terminal predicates and join keys. Aggregation supports accumulator closures,
  explicit seeds and an optional final result selector.
• Match .NET paging behavior for nonpositive skip and take counts. Ignore null
  values in Enumerable averages; nonempty all-null sequences return null, while
  empty Enumerable averages continue to throw UnderflowException.
• Document PHP numeric/type semantics, closure restrictions and provider support.
  SQL/custom providers must implement the new operations and expression nodes or
  reject them explicitly; no automatic client-side fallback is introduced.
• Expand validation to 383 tests and 1,411 assertions, with CI on PHP 8.3–8.5.

Compatibility notes: custom implementations of IEnumerable and IQueryable
must implement the added methods. Enumerable average() now has a nullable return
type. cast() checks types without coercion and rejects null; sequence generators
use PHP int|float limits. aggregateBy() currently supports fixed seeds only.