feat: self-hosting progress - Nim backend, parser fixes, 64 struct fields, 13/14 modules check

src_bux/ast.bux

@@ -244,7 +244,7 @@ struct Decl {
     retType: *TypeExpr,
     // Body
     refBody: *Block,
-    // Struct fields (up to 8)
+    // Struct fields (up to 64)
     fieldCount: int,
     field0: StructField,
     field1: StructField,
@@ -254,6 +254,62 @@ struct Decl {
     field5: StructField,
     field6: StructField,
     field7: StructField,
+    field8: StructField,
+    field9: StructField,
+    field10: StructField,
+    field11: StructField,
+    field12: StructField,
+    field13: StructField,
+    field14: StructField,
+    field15: StructField,
+    field16: StructField,
+    field17: StructField,
+    field18: StructField,
+    field19: StructField,
+    field20: StructField,
+    field21: StructField,
+    field22: StructField,
+    field23: StructField,
+    field24: StructField,
+    field25: StructField,
+    field26: StructField,
+    field27: StructField,
+    field28: StructField,
+    field29: StructField,
+    field30: StructField,
+    field31: StructField,
+    field32: StructField,
+    field33: StructField,
+    field34: StructField,
+    field35: StructField,
+    field36: StructField,
+    field37: StructField,
+    field38: StructField,
+    field39: StructField,
+    field40: StructField,
+    field41: StructField,
+    field42: StructField,
+    field43: StructField,
+    field44: StructField,
+    field45: StructField,
+    field46: StructField,
+    field47: StructField,
+    field48: StructField,
+    field49: StructField,
+    field50: StructField,
+    field51: StructField,
+    field52: StructField,
+    field53: StructField,
+    field54: StructField,
+    field55: StructField,
+    field56: StructField,
+    field57: StructField,
+    field58: StructField,
+    field59: StructField,
+    field60: StructField,
+    field61: StructField,
+    field62: StructField,
+    field63: StructField,
     // Enum variants (up to 8)
     variantCount: int,
     variant0: EnumVariant,