feat: make unsaved settings obvious

src/tabs/MainTab.tsx

@@ -1,12 +1,36 @@
-import { Box, VStack } from '@chakra-ui/react';
+import { Alert, AlertIcon, Box, Button, Flex, Text, VStack } from '@chakra-ui/react';
 import { SelectFile } from '../components/SelectFile';
 
 import { FileListing } from '~/features/file-listing/FileListing';
+import { useAppDispatch, useAppSelector } from '~/hooks.ts';
+import { selectIsSettingsNotSaved } from '~/features/settings/settingsSelector.ts';
+import { commitStagingChange } from '~/features/settings/settingsSlice.ts';
 
 export function MainTab() {
+  const dispatch = useAppDispatch();
+  const isSettingsNotSaved = useAppSelector(selectIsSettingsNotSaved);
+  const onClickSaveSettings = () => {
+    dispatch(commitStagingChange());
+  };
+
   return (
     <Box h="full" w="full" pt="4">
       <VStack gap="3">
+        {isSettingsNotSaved && (
+          <Alert borderRadius={7} maxW={400} status="warning">
+            <AlertIcon />
+            <Flex flexDir="row" alignItems="center" flexGrow={1} justifyContent="space-between">
+              <Text m={0}>
+                有尚未储存的设置，
+                <br />
+                设定将在保存后生效
+              </Text>
+              <Button type="button" ml={3} size="md" onClick={onClickSaveSettings}>
+                立即储存
+              </Button>
+            </Flex>
+          </Alert>
+        )}
         <SelectFile />
 
         <Box w="full">