Support some, ok and err wrappers and untyped function inputs

Track the LScript changes since the grammar was first written:

- some, ok and err are reserved prefix operators and wrapper patterns;
  the old |.some/|.ok/|.err forms and postfix/prefix ! are rejected
- function literal inputs may omit their type annotation, and tuple
  components may omit theirs; an empty typed tuple pattern is now just
  the unit pattern
- migrate fixtures, corpus, queries, CST contract and Rust tests

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

test/fixtures/valid/containers.ls

@@ -7,7 +7,7 @@ more_codes := [...codes, 'failed' => 500]
 empty_numbers: []i32: []
 empty_codes: [str]i32: []
 optional_numbers: []i32?: nil
-optional_elements: []{i32?}: [nil, 1->|.some]
+optional_elements: []{i32?}: [nil, some 1]
 
 Options :: &{
     name: str: 'default'