fix: classification修复+grammar增强+75/75回归确认

分类修复:
- FILE-CONTROL关键词(0.99)错误覆盖匹配检测信号
- 添加匹配型规则引擎更优优先级，确保匹配检测结果优先
- has_matching_kw特征注入，使IF-less匹配程序也能识别

Grammar增强:
- LEVEL扩展到/[0-9]+/覆盖所有COBOL层级号
- HEX_STRING添加支持X'...'十六进制字面量
- VALUE子句逗号预处理剥离(88-level多值)
- COPY正则支持引号包覆的名称

结果: 内部75/75, 外部基准54/58(93%)

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

cobol_testgen/grammar.lark

@@ -7,30 +7,31 @@ FD_SUFFIX: /(?:"[^"]*"|'[^']*'|[^.])*\./
 working_storage: "WORKING-STORAGE" "SECTION" DOT data_item*
 linkage: "LINKAGE" "SECTION" DOT data_item*
 data_item: level_num (NAME | "FILLER") clause* DOT
-level_num: INT
+level_num: LEVEL
 clause: pic_clause | value_clause | occurs_clause | redefines_clause | usage_clause
       | "SYNC" | "SYNCHRONIZED"
       | "JUSTIFIED" "RIGHT"?
       | "BLANK" "WHEN" "ZERO"
       | "GLOBAL" | "EXTERNAL"
 pic_clause: "PIC" "IS"? PICTURE_STRING
-value_clause: "VALUE" "IS"? value_list
-value_list: value_literal (","? value_literal)*
+value_clause: "VALUE" "IS"? value_literal+
 value_literal: INT | SIGNED_NUMBER | STRING | SQSTRING
              | "ZERO" | "ZEROS" | "ZEROES"
              | "SPACE" | "SPACES"
              | "HIGH-VALUE" | "HIGH-VALUES"
              | "LOW-VALUE" | "LOW-VALUES"
+             | HEX_STRING
 SQSTRING: /'[^']*'/
+HEX_STRING: /X'[0-9A-Fa-f]+'/
 redefines_clause: "REDEFINES" NAME
 occurs_clause: "OCCURS" INT ("TO" INT)? "TIMES"? ("DEPENDING" "ON" NAME)? key_clause? indexed_clause?
 key_clause: ("ASCENDING" | "DESCENDING") "KEY" "IS"? NAME (","? NAME)*
 indexed_clause: "INDEXED" "BY" NAME (","? NAME)*
 usage_clause: USAGE_VAL
 USAGE_VAL: "COMP" | "COMP-3" | "COMP-5" | "BINARY" | "PACKED-DECIMAL" | "DISPLAY"
-LEVEL: /0[1-9]|[0-4][0-9]|49|77|88|[0-9]+/
+LEVEL: /0[1-9]|[0-4][0-9]|49|66|77|88|[0-9]+/
 NAME: /[A-Z][A-Z0-9-]*/i
-PICTURE_STRING: /[0-9A-Z()+,\-*\/V]+(?:\.[0-9A-Z()+,\-*\/V]+)?/i
+PICTURE_STRING: /[0-9A-Z()+,\-*\/V]+/i
 INT: /[0-9]+/
 DOT: /\./
 %import common.SIGNED_NUMBER