feat(tcloo): add document-local TclOO completions, signature help and hints

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.

server/src/tools/completion_items.py

@@ -33,6 +33,7 @@ VARIABLE_KINDS = {
     lsp.CompletionItemKind.Constant,
 }
 COMMAND_KINDS = {
+    lsp.CompletionItemKind.Class,
     lsp.CompletionItemKind.Function,
     lsp.CompletionItemKind.Method,
     lsp.CompletionItemKind.Constructor,