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/lsp_server.py

@@ -75,6 +75,10 @@ from tools.semantic_tokens import (
     _Highlighter,
 )
 from tools.signature_help import build_signature_help
+from tools.tcloo_arguments import method_signature_help
+from tclint.lexer import TclSyntaxError
+from tools.tcloo_completion import parse_completion_source, tcloo_completions
+from tools.tcloo_symbols import class_completion_items
 from tools.tcl_command_completion import (
     TCL_COMMAND_ITEMS,
     TCL_COMMAND_NAMES,
@@ -278,6 +282,9 @@ def on_completion(params: lsp.CompletionParams) -> lsp.CompletionList:
     doc = LSP_SERVER.workspace.get_text_document(params.text_document.uri)
     position = params.position
     source_lines = LSP_SERVER.get_lines(doc)
+    oo_items = tcloo_completions(source_lines, position)
+    if oo_items is not None:
+        return lsp.CompletionList(is_incomplete=False, items=oo_items)
     array_items = array_element_completions(
         source_lines, position, LSP_SERVER.navigation_snapshot().values(),
         str(pathlib.Path(uris.to_fs_path(doc.uri))),
@@ -334,7 +341,12 @@ def on_completion(params: lsp.CompletionParams) -> lsp.CompletionList:
     ):
         return lsp.CompletionList(is_incomplete=False, items=[])
 
-    tree = LSP_SERVER.get_tree(doc)
+    try:
+        tree = LSP_SERVER.get_tree(doc)
+    except TclSyntaxError:
+        tree = parse_completion_source(doc.source)
+        if tree is None:
+            return lsp.CompletionList(is_incomplete=False, items=[])
     globals_set, procs_locals, proc_ranges = LSP_SERVER.variable_index_for_document(
         doc, tree
     )
@@ -347,6 +359,7 @@ def on_completion(params: lsp.CompletionParams) -> lsp.CompletionList:
             break
 
     candidates: list[tuple[int, lsp.CompletionItem]] = []
+    candidates.extend((0, item) for item in class_completion_items(tree))
     for name in sorted(local_names - globals_set):
         candidates.append(
             (
@@ -457,7 +470,15 @@ def on_completion(params: lsp.CompletionParams) -> lsp.CompletionList:
 )
 def signature_help(params: lsp.SignatureHelpParams) -> lsp.SignatureHelp | None:
     document = LSP_SERVER.workspace.get_text_document(params.text_document.uri)
-    tree = LSP_SERVER.get_tree(document)
+    method_help = method_signature_help(document.source, params.position)
+    if method_help is not None:
+        return method_help
+    try:
+        tree = LSP_SERVER.get_tree(document)
+    except TclSyntaxError:
+        tree = parse_completion_source(document.source)
+        if tree is None:
+            return None
 
     custom_signatures, custom_docs = LSP_SERVER.proc_metadata_snapshot(
         document.path
@@ -541,6 +562,7 @@ def semantic_tokens(params: lsp.SemanticTokensParams):
 
     # Reuse cached AST
     tree = LSP_SERVER.get_tree(document)
+    hl.highlight_classes(tree)
     tree.accept(hl, recurse=True)
 
     tokens = hl.tokens()