feat(core): drop doc onto split view (#9487)

fix AF-2068, AF-2069, AF-1175, AF-2061, AF-2079, AF-2034, AF-2080, AF-1960, AF-2081

1. replace `dnd-kit` with `@atlaskit/pragmatic-drag-and-drop`
2. allow creating split views by drag & drop the following
   a. WorkbenchLinks (route links), like journals, trash, all docs
   b. doc refs
   c. tags/collection
3. style adjustments to split view
4. remove split view's feature flag and make it GA for electron

https://github.com/user-attachments/assets/6a3e4a25-faa2-4215-8eb0-983f44db6e8c

packages/frontend/core/src/desktop/components/app-container/styles.css.ts

@@ -78,27 +78,25 @@ export const mainContainerStyle = style({
   width: '100%',
   display: 'flex',
   flex: 1,
-  overflow: 'clip',
   maxWidth: '100%',
 
   selectors: {
     '&[data-client-border="true"]': {
       borderRadius: 6,
-      margin: '8px',
-      overflow: 'clip',
+      padding: '8px',
       '@media': {
         print: {
           overflow: 'visible',
-          margin: '0px',
+          padding: '0px',
           borderRadius: '0px',
         },
       },
     },
     '&[data-client-border="true"][data-side-bar-open="true"]': {
-      marginLeft: 0,
+      paddingLeft: 0,
     },
     '&[data-client-border="true"][data-is-desktop="true"]': {
-      marginTop: 0,
+      paddingTop: 0,
     },
     '&[data-client-border="false"][data-is-desktop="true"][data-side-bar-open="true"]':
       {

packages/frontend/core/src/desktop/pages/journals/index.tsx

@@ -0,0 +1,11 @@
+import { useJournalRouteHelper } from '@affine/core/components/hooks/use-journal';
+import { useEffect } from 'react';
+
+// this route page acts as a redirector to today's journal
+export const Component = () => {
+  const { openToday } = useJournalRouteHelper();
+  useEffect(() => {
+    openToday({ replaceHistory: true });
+  }, [openToday]);
+  return null;
+};

packages/frontend/core/src/desktop/workbench-router.ts

@@ -33,6 +33,10 @@ export const workbenchRoutes = [
     path: '/:pageId/attachments/:attachmentId',
     lazy: () => import('./pages/workspace/attachment/index'),
   },
+  {
+    path: '/journals',
+    lazy: () => import('./pages/journals'),
+  },
   {
     path: '*',
     lazy: () => import('./pages/404'),