新增：固定Header功能；

Signed-off-by: iczer <1126263215@qq.com>

src/store/modules/setting.js

@@ -27,6 +27,9 @@ export default {
     },
     setWeekMode(state, weekMode) {
       state.weekMode = weekMode
+    },
+    setFixedHeader(state, fixedHeader) {
+      state.fixedHeader = fixedHeader
     }
   }
 }