Add a unique numeric ID to each fiber allocation, enabling fibers to be used as map keys. This includes updating the hash function for OBJ_FIBER to return the fiber's ID, modifying key validation to accept fibers, updating documentation to describe the new capability, and adjusting all relevant test expectations and error messages.
- Compile empty `()` as a valid method signature distinct from no parentheses
- Update `call()`, `clear()`, `run()`, `try()`, and `yield()` to use empty argument lists
- Revise documentation across multiple files to reflect new signature semantics
Add `^category` front matter to all language, types, and reference doc pages for site navigation restructuring. Replace `:::wren` and `:::java` code block annotations with `:::dart` across multiple files. Create new stub pages for core-libraries, embedding-api, and contributing under the reference category. Remove the old embedding and getting-involved stub pages.
