feat: 搜索框下滚动、本地服务卡片排序、拖拽末位修复

- 恢复内容区内部滚动：页头/搜索框固定，滚动区域从搜索框下方开始；侧栏跟随内容滚动，侧栏滚轮驱动内容区
- v22：本地服务以 card 行 local-service 参与排序；首页按卡片顺序渲染，后台可拖动排序
- 本地服务卡片后端禁止删除/改名/配置分组
- 修复向下拖动时插到目标之后，倒数第二项可拖到最后
- 验证：搜索框位置固定、侧栏 scrollTop 跟随、本地服务与倒数第二拖末位均落库、首页顺序一致

src/db/cards.rs

@@ -117,16 +117,23 @@ pub fn create(conn: &mut Connection, new: NewCard) -> Result<i64, StashError> {
 }
 
 pub fn update(conn: &mut Connection, id: i64, patch: UpdateCard) -> Result<(), StashError> {
-    let current: Option<(String, i64)> = conn
-        .query_row("SELECT title, sort FROM card WHERE id = ?1", [id], |row| {
-            Ok((row.get(0)?, row.get(1)?))
-        })
+    let current: Option<(String, String, i64)> = conn
+        .query_row(
+            "SELECT key, title, sort FROM card WHERE id = ?1",
+            [id],
+            |row| Ok((row.get(0)?, row.get(1)?, row.get(2)?)),
+        )
         .optional()
         .map_err(map_error)?;
 
-    let Some((current_title, current_sort)) = current else {
+    let Some((current_key, current_title, current_sort)) = current else {
         return Err(StashError::NotFound(format!("卡片不存在: {id}")));
     };
+    if current_key == "local-service" && patch.title.is_some() {
+        return Err(StashError::InvalidDirectory(
+            "本地服务卡片由系统生成，不能改名".into(),
+        ));
+    }
 
     let title = match patch.title {
         Some(title) => {
@@ -152,6 +159,15 @@ pub fn update(conn: &mut Connection, id: i64, patch: UpdateCard) -> Result<(), S
 }
 
 pub fn remove(conn: &Connection, id: i64) -> Result<(), StashError> {
+    let key: Option<String> = conn
+        .query_row("SELECT key FROM card WHERE id = ?1", [id], |row| row.get(0))
+        .optional()
+        .map_err(map_error)?;
+    if key.as_deref() == Some("local-service") {
+        return Err(StashError::InvalidDirectory(
+            "本地服务卡片由系统生成，不能删除".into(),
+        ));
+    }
     let removed = conn
         .execute("DELETE FROM card WHERE id = ?1", [id])
         .map_err(map_error)?;
@@ -168,6 +184,16 @@ pub fn set_groups(
     id: i64,
     groups: Vec<CardGroupInput>,
 ) -> Result<(), StashError> {
+    let key: Option<String> = conn
+        .query_row("SELECT key FROM card WHERE id = ?1", [id], |row| row.get(0))
+        .optional()
+        .map_err(map_error)?;
+    if key.as_deref() == Some("local-service") {
+        return Err(StashError::InvalidDirectory(
+            "本地服务卡片由系统生成，不能配置分组".into(),
+        ));
+    }
+
     let exists: i64 = conn
         .query_row("SELECT COUNT(*) FROM card WHERE id = ?1", [id], |row| row.get(0))
         .map_err(map_error)?;