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>

tools/ludic-tools/ludic_syntax.h

@@ -52,8 +52,8 @@ typedef struct {
  * mirror the compiler's parser: anything parse_decl() dispatches on is a
  * declaration keyword, anything stmt() dispatches on is a statement keyword. */
 static const char* LUDIC_KW_DECL[] = {
-    "game","module","import","component","struct","archetype","ui","scene","layer",
-    "const","var","export","fn","pure","extern","system","edge","start","on", 0
+    "game","module","import","component","struct","archetype","enum","ui","scene","layer",
+    "const","var","fn","extern","system","start","on", 0
 };
 static const char* LUDIC_KW_CLAUSE[] = {
     "phase","query","reads","writes","needs","uses",