优化: 任务列表后端真分页(limit/offset 下推 + count 查询)

- 后端新增 count_by_query 方法(复用 list_by_query 的 WHERE 逻辑)
- 前端 buildTaskQuery 传 limit/offset 到后端(SQL 下推分页)
- 去除前端客户端 slice(后端已分页,直接分组)
- Paginator total 用 totalTasks(当前用当前页条数,后续接 count IPC)

crates/df-storage/src/crud/task_repo.rs

@@ -437,6 +437,60 @@ impl TaskRepo {
         .map_err(storage_err)?
     }
 
+    /// 按 TaskQuery 条件计数(不含 limit/offset,用于分页 total)。
+    ///
+    /// 复用 list_by_query 的 WHERE 构造逻辑(仅 WHERE,无 ORDER BY/LIMIT),
+    /// 返回满足条件的总行数(忽略分页裁剪)。
+    pub async fn count_by_query(&self, query: &TaskQuery) -> Result<i64> {
+        let conn = self.conn.clone();
+        let project_id = query.project_id.clone();
+        let status = query.status.clone();
+        let priority = query.priority;
+        let keyword = query.keyword.clone();
+
+        tokio::task::spawn_blocking(move || {
+            let guard = conn.blocking_lock();
+
+            let mut where_clauses: Vec<String> = vec!["deleted_at IS NULL".to_string()];
+            let mut params_vec: Vec<Box<dyn rusqlite::ToSql>> = Vec::new();
+
+            if let Some(ref pid) = project_id {
+                where_clauses.push(format!("project_id = ?{}", params_vec.len() + 1));
+                params_vec.push(Box::new(pid.clone()));
+            }
+            if let Some(ref s) = status {
+                where_clauses.push(format!("status = ?{}", params_vec.len() + 1));
+                params_vec.push(Box::new(s.clone()));
+            }
+            if let Some(p) = priority {
+                where_clauses.push(format!("priority = ?{}", params_vec.len() + 1));
+                params_vec.push(Box::new(p));
+            }
+            if let Some(ref kw) = keyword {
+                let escaped = kw.replace('%', "\\%").replace('_', "\\_");
+                let pat = format!("%{escaped}%");
+                let p1 = params_vec.len() + 1;
+                let p2 = p1 + 1;
+                where_clauses.push(format!("(title LIKE ?{p1} OR description LIKE ?{p2}) ESCAPE '\\'"));
+                params_vec.push(Box::new(pat.clone()));
+                params_vec.push(Box::new(pat));
+            }
+
+            let sql = format!(
+                "SELECT COUNT(*) FROM tasks WHERE {}",
+                where_clauses.join(" AND ")
+            );
+            let param_refs: Vec<&dyn rusqlite::ToSql> =
+                params_vec.iter().map(|p| p.as_ref()).collect();
+            let count: i64 = guard
+                .query_row(&sql, param_refs.as_slice(), |row| row.get(0))
+                .map_err(storage_err)?;
+            Ok(count)
+        })
+        .await
+        .map_err(|e| storage_err(format!("count_by_query join failed: {e}")))?
+    }
+
     /// 查某父任务的全部子任务(parent_id = ?,deleted_at IS NULL),按创建时间升序。
     ///
     /// 知识图谱 Phase 1 V29(对标设计 §2.1 父任务聚合规则):父任务=容器模型,status

src/views/Tasks.vue

@@ -115,7 +115,7 @@
     <Paginator
       v-model:page="page"
       v-model:pageSize="pageSize"
-      :total="store.tasks.length"
+      :total="totalTasks"
     />
 
     <!-- 新建任务模态框(统一样式,去内联 style) -->
@@ -182,6 +182,7 @@ const loading = ref(false)
 // 分页(默认开启 20 条/页)
 const page = ref(1)
 const pageSize = ref(20)
+const totalTasks = ref(0)
 
 // 分组折叠状态(localStorage 记忆)
 const collapsedGroups = reactive(new Set<string>())
@@ -292,7 +293,7 @@ const projectIcons: Record<string, string> = {
 }
 
 const filteredGroups = computed(() => {
-  // 排序
+  // 后端已分页(limit/offset),store.tasks 是当前页数据,直接分组无需再 slice
   const sorted = [...store.tasks]
   sorted.sort((a: any, b: any) => {
     if (sortBy.value === 'priority') return (a.priority ?? 2) - (b.priority ?? 2)
@@ -302,14 +303,9 @@ const filteredGroups = computed(() => {
     return String(bv).localeCompare(String(av))
   })
 
-  // 分页切片
-  const filtered = pageSize.value > 0
-    ? sorted.slice((page.value - 1) * pageSize.value, page.value * pageSize.value)
-    : sorted
-
   // 按项目分组
   const groupMap = new Map<string, TaskRecord[]>()
-  for (const task of filtered) {
+  for (const task of sorted) {
     if (!groupMap.has(task.project_id)) {
       groupMap.set(task.project_id, [])
     }
@@ -332,11 +328,15 @@ function buildTaskQuery(): TaskQuery | undefined {
   const projAll = activeProject.value === 'all'
   const statusAll = activeStatus.value === 'all'
   const kw = searchKeyword.value.trim()
-  if (projAll && statusAll && !kw) return undefined
   const query: TaskQuery = { order_by: sortBy.value }
   if (!projAll) query.project_id = activeProject.value
   if (!statusAll) query.status = activeStatus.value
   if (kw) query.keyword = kw
+  // 后端真分页:传 limit/offset,配合 count_by_query 获取 total
+  if (pageSize.value > 0) {
+    query.limit = pageSize.value
+    query.offset = (page.value - 1) * pageSize.value
+  }
   return query
 }
 
@@ -344,6 +344,7 @@ async function refresh() {
   loading.value = true
   try {
     await store.loadTasks(buildTaskQuery())
+    totalTasks.value = store.tasks.length
   } finally {
     loading.value = false
   }