Phase 4b: enum types name magic-int value spaces

enum Name { A, B, C } declares named int constants; Enum.Variant is a
compile-time int (index by declaration order), usable in match patterns,
comparisons, setreg. New: parse_enum + dispatch, enum_ordinal resolver
(emit_core), Enum.Variant handling (emit_expr). Scoped to a naming layer over
int (no enum-typed variables), so register/save semantics are untouched.

combat.ludic battle menus dispatch on KnightAct/MageAct instead of 0..3;
chronorift golden byte-identical. Editor vocab (ludic_syntax.h, JetBrains,
TextMate, emacs) gained enum, dropped retired edge/export/pure decl keywords;
check-vocabulary + test-tools 28/0. when/if kept by choice; bitwise stays
functions. Reseeded, fixpoint holds, test.sh 14/14.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

selfhost/emit_core.ludic

@@ -119,6 +119,21 @@ fn find_global(name: ptr) -> Node {
   }
   return ptr_null()
 }
+
+# `Enum.Variant` -> the variant's ordinal (its index), or -1 if `ename` names no
+# enum with that variant. Enum names live in `prog` like any other declaration.
+fn enum_ordinal(ename: ptr, vname: ptr) -> int {
+  let i = 0
+  while i < len(prog) {
+    let d = prog[i]
+    if d.kind == N_ENUM and streq(d.s, ename) {
+      let j = 0
+      while j < len(d.kids) { if streq(d.kids[j].s, vname) { return j };  j = j + 1 }
+    }
+    i = i + 1
+  }
+  return 0 - 1
+}
 fn find_fn(name: ptr) -> Node {
   let i = 0
   while i < len(prog) { let d = prog[i];  if d.kind == N_FN and streq(d.s, name) { return d };  i = i + 1 }