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/invalid/keyword_ok_identifier.ls

@@ -0,0 +1 @@
+ok :: @ value { value }