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/control.ls

@@ -11,7 +11,7 @@ choose_block: (bit, i32, i32) -> i32: @ (condition: bit, when_true: i32, when_fa
 first_positive: []i32 -> i32?: @ values: []i32 {
     for value in values {
         if value > 0 {
-            return value->|.some
+            return some value
         }
     }
     nil