fix: correct bitfield decoder using mask extraction, fix command_node

- Switch bitfield decoder from shift-based to mask-based extraction (var>>pos & mask)
  fixes non-power-of-2 bitfields like 6-bit command_node flags
- Fix MultiTypeFix to handle CaseExprTypeOnlyNumber/OnlyBool variants
- Update minecraft-data command_node bitfield order for all 1.21.8+ versions
  to LSB-first convention (matches reverse encoder/decoder)
- Implement SwitchDecoder for extraNodeData via compareTo visitor
- DeclareCommands now decodes successfully (was EOF)
- Add 6 regression tests (entity_equipment, metadata, recipes, commands)

mc/proto_generator/native_decoder.go

@@ -225,7 +225,7 @@ func MultiTypeFix(s string, t *CaseExprType) (e ast.Expr) {
 		*t = ct
 		return
 	}
-	if *t == ct {
+	if *t == ct || (*t == CaseExprTypeOnlyNumber && ct == CaseExprTypeNumber) || (*t == CaseExprTypeOnlyBool && ct == CaseExprTypeBool) || (*t == CaseExprTypeNumber && ct == CaseExprTypeOnlyNumber) || (*t == CaseExprTypeBool && ct == CaseExprTypeOnlyBool) {
 		return
 	}
 
@@ -400,6 +400,7 @@ func BitFieldDecoder(g *Generator, varToSet ast.Expr, dataRaw any, name string)
 	}
 	s = append(s, packedVarStmt)
 	s = append(s, stmts...)
+	slices.Reverse(data)
 	lShiftBy := 0
 	for _, field := range data {
 		var fieldTypeProtodef string
@@ -413,16 +414,13 @@ func BitFieldDecoder(g *Generator, varToSet ast.Expr, dataRaw any, name string)
 			return
 		}
 
-		rShiftBy := totalSize - field.Size
 		fieldToSet := SelectorExprAndStr(varToSet, util2.CamelCase(field.Name))
 
+		mask := (1 << field.Size) - 1
 		var getDataExpr ast.Expr
-		getDataExpr = RightShift(
-			LeftShift(
-				Ident(packed),
-				NumLit(lShiftBy)),
-			NumLit(rShiftBy),
-		)
+		getDataExpr = BinAnd(
+			RightShift(Ident(packed), NumLit(lShiftBy)),
+			NumLit(mask))
 		if fieldTypeProtodef == "bool" {
 			getDataExpr = Equals(getDataExpr, NumLit(1))
 		} else if fieldTypeProtodef != packedTypeProtodef {