fix: code review issues #1-#9

1. cond.py: 删除重复裸字段代码块 (dedup bare field)
2. coverage.py: 移除_mark_perform无条件fallback (虚假覆盖)
3. pipeline_bridge.py: except:pass加日志记录异常
4. __init__.py: generate_data文档更新 (copybook_dirs等)
5. cond.py: is_field贪婪→非贪婪.*→.*?
6. coverage.py: 移除残留无条件Enter+Skip标记

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

cobol_testgen/cond.py

@@ -269,7 +269,7 @@ def evaluate_tree(tree, assignment):
 
 def is_field(name, fields):
     # Strip subscript: WS-ITEM-STATUS(WS-INDEX-VAR) -> WS-ITEM-STATUS
-    bare = re.sub(r'\s*\(.*\)\s*$', '', name).strip()
+    bare = re.sub(r'\s*\(.*?\)\s*$', '', name).strip()
     for f in fields:
         if f['name'] == bare.upper():
             return True