fix: 第七轮深度搜索审计修复 — 20项

- HIGH: isdecimal() → re.match() for PMID (non-ASCII digit crash)
- HIGH: boolean_operator 应用到字段分组和无标签词（AND/OR 错误）
- HIGH: Cursor 分页 pub_date 优先（article_date 导致数据错位）
- Parser: parse 异常处理器清理字段标签/布尔符/引号
- Parser: _parse_range date:year 反向交换（第4分支）
- Parser: MAX_TERMS 保护、TITLE/ABSTRACT 大写键补充
- Engine: best_match 排序剥离字段标签
- Engine: year_from/year_to is not None（年份=0 被 falsy 跳过）
- Engine: _single_term_condition SB 字段全量分发
- Engine: journal_tiers/nlm_subsets 空条件预警（0结果保障）
- Engine: ATM 展开和 _expand_mesh_tag_ids pass → logger.exception
- Engine: 降级 regex [\w/: -] 兼容 [MH:noexp] 冒号
- Frontend: syncSearchToUrl 移到 finally 块
- Frontend: 年份滑块/resetAllFilters 清除 URL 日期
- Frontend: Null cursor 日期安全守卫
- Docs: 新增 P7-1~P7-20 记录，测试数更新至 276

frontend/src/views/app/SearchView.vue

@@ -89,6 +89,7 @@ function onYearSliderChange(val: any) {
   yearFromStr.value = String(val[0])
   yearToStr.value = String(val[1])
   datePreset.value = null
+  urlDateFrom.value = ''; urlDateTo.value = ''  // P6: clear stale URL dates
   if (_sliderTimer) clearTimeout(_sliderTimer)
   _sliderTimer = setTimeout(() => goToPage(1), 250)
 }
@@ -352,20 +353,26 @@ const { page, total, goToPage } = usePagination({
         if (items.length > 0) {
           const last = items[items.length - 1]
           keysetCursors.value[p + 1] = {
-            cursor_date: last.article_date || last.pub_date || '',
+            cursor_date: last.pub_date || last.article_date || '',
             cursor_id: last.id,
           }
+          // 当两个日期都为空时，不设游标（避免空串 fromisoformat 失败）
+          if (!last.pub_date && !last.article_date) {
+            delete keysetCursors.value[p + 1]
+          }
         }
       } else {
         total.value = data.total || 0
       }
       yearCounts.value = data.year_counts || []
-      syncSearchToUrl()
     } catch (e: any) {
       if (e?.name === 'CanceledError' || e?.code === 'ERR_CANCELED') return
       toast.apiError(e, '搜索失败，请重试')
     }
-    finally { if (gen === searchGeneration.value) loading.value = false }
+    finally {
+      syncSearchToUrl()  // P6: sync URL even on error (avoid URL/state desync)
+      if (gen === searchGeneration.value) loading.value = false
+    }
   },
   pageSize: pageSize.value,
 })
@@ -518,6 +525,7 @@ function syncSearchToUrl() {
 
 function resetAllFilters() {
   yearFromStr.value = ''; yearToStr.value = ''
+  urlDateFrom.value = ''; urlDateTo.value = ''  // P6: clear stale URL dates
   datePreset.value = null
   selectedTiers.value = []
   selectedTags.value = []