Add a generic `contains` implementation on the `Sequence` base class, removing the duplicate method from `List`. This allows all sequence types (including Range) to use the method without per-class redefinition. Include new test files for `List.contains` and `Range.contains` covering ordered, backwards, and exclusive ranges.
Adds a new `any` method to the Sequence class that tests whether any element
in the sequence passes the given predicate function, returning true on the
first match or false if none match. Includes documentation, core library
source update, and three new test files covering basic functionality,
non-boolean return values, and non-function argument error handling.
Add `join` and `join(sep)` methods to the `Sequence` class, allowing any sequence to produce a concatenated string of its elements with an optional separator. Refactor `List.toString` to delegate to `join(", ")` with bracket wrapping, removing the manual iteration logic from List. Include new test files for List, Range, and String join behavior, plus runtime error tests for non-string separators.
Add String as a subclass of Sequence in core.wren and implement the iterator protocol for strings in wren_core.c. The string_iterate native advances through UTF-8 code point boundaries, while string_iteratorValue extracts the full code point at a given byte index. Includes comprehensive test coverage for iteration, edge cases (empty strings, mid-sequence positions), and error handling for invalid iterator types and out-of-bounds indices. Also updates documentation for String, List, and Sequence classes with iterator protocol details and usage examples.