Add conservative, document-local TclOO type inference and tooling so the server
can offer method completions, signature help, and inlay parameter hints for
statically resolvable TclOO receivers (including `new`/`create`, `my`, and
simple return-chains). Also surface class names as completion items and emit
semantic tokens for class declarations/references.
Notable changes:
- New tcloo_* tools: completion, symbols, and argument parsing; integrated into
on_completion, signature_help, inlay hint generation and semantic token
highlighting. Completions are returned early when an OO receiver context is
detected.
- Use a completion-friendly parser fallback when the main AST fails (TclSyntaxError)
so editing-in-progress code still yields useful completions.
- Add CompletionItemKind.Class to command kinds, exclude class items from the
poco completion name cache, and include new unit tests for the TclOO helpers.