fix(editor): cleanup transformer middleware slot subscriptions (#12630)

<!-- This is an auto-generated comment: release notes by coderabbit.ai -->

## Summary by CodeRabbit

- **New Features**
  - Improved resource management by introducing explicit cleanup for various middleware components, ensuring that resources are properly released when no longer needed.

- **Refactor**
  - Updated middleware logic to support cleanup functions, enhancing the stability and performance of the application by preventing potential memory leaks.

- **Chores**
  - Enhanced lifecycle management in core systems to automatically dispose of resources when appropriate.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

blocksuite/affine/widgets/drag-handle/src/middleware/blocks-filter.ts

@@ -40,7 +40,7 @@ export const gfxBlocksFilter = (
   }
 
   return ({ slots, transformerConfigs }) => {
-    slots.beforeExport.subscribe(payload => {
+    const beforeExportSubscription = slots.beforeExport.subscribe(payload => {
       if (payload.type !== 'block') {
         return;
       }
@@ -54,7 +54,7 @@ export const gfxBlocksFilter = (
       }
     });
 
-    slots.afterExport.subscribe(payload => {
+    const afterExportSubscription = slots.afterExport.subscribe(payload => {
       if (payload.type !== 'block') {
         return;
       }
@@ -110,5 +110,10 @@ export const gfxBlocksFilter = (
         });
       }
     });
+
+    return () => {
+      beforeExportSubscription.unsubscribe();
+      afterExportSubscription.unsubscribe();
+    };
   };
 };

blocksuite/affine/widgets/drag-handle/src/middleware/new-id-cross-doc.ts

@@ -9,36 +9,45 @@ export const newIdCrossDoc =
     let samePage = false;
     const oldToNewIdMap = new Map<string, string>();
 
-    slots.beforeImport.subscribe(payload => {
-      if (payload.type === 'slice') {
-        samePage = payload.snapshot.pageId === std.store.id;
+    const beforeImportSliceSubscription = slots.beforeImport.subscribe(
+      payload => {
+        if (payload.type === 'slice') {
+          samePage = payload.snapshot.pageId === std.store.id;
+        }
+        if (payload.type === 'block' && !samePage) {
+          const newId = std.workspace.idGenerator();
+
+          oldToNewIdMap.set(payload.snapshot.id, newId);
+          payload.snapshot.id = newId;
+        }
       }
-      if (payload.type === 'block' && !samePage) {
-        const newId = std.workspace.idGenerator();
+    );
 
-        oldToNewIdMap.set(payload.snapshot.id, newId);
-        payload.snapshot.id = newId;
+    const afterImportBlockSubscription = slots.afterImport.subscribe(
+      payload => {
+        if (
+          !samePage &&
+          payload.type === 'block' &&
+          matchModels(payload.model, [DatabaseBlockModel])
+        ) {
+          const originalCells = payload.model.props.cells;
+          const newCells = {
+            ...originalCells,
+          };
+
+          Object.keys(originalCells).forEach(cellId => {
+            if (oldToNewIdMap.has(cellId)) {
+              newCells[oldToNewIdMap.get(cellId)!] = originalCells[cellId];
+            }
+          });
+
+          payload.model.props.cells$.value = newCells;
+        }
       }
-    });
+    );
 
-    slots.afterImport.subscribe(payload => {
-      if (
-        !samePage &&
-        payload.type === 'block' &&
-        matchModels(payload.model, [DatabaseBlockModel])
-      ) {
-        const originalCells = payload.model.props.cells;
-        const newCells = {
-          ...originalCells,
-        };
-
-        Object.keys(originalCells).forEach(cellId => {
-          if (oldToNewIdMap.has(cellId)) {
-            newCells[oldToNewIdMap.get(cellId)!] = originalCells[cellId];
-          }
-        });
-
-        payload.model.props.cells$.value = newCells;
-      }
-    });
+    return () => {
+      beforeImportSliceSubscription.unsubscribe();
+      afterImportBlockSubscription.unsubscribe();
+    };
   };

blocksuite/affine/widgets/drag-handle/src/middleware/reorder-list.ts

@@ -7,19 +7,25 @@ import type { TransformerMiddleware } from '@blocksuite/store';
 export const reorderList =
   (std: BlockStdScope): TransformerMiddleware =>
   ({ slots }) => {
-    slots.afterImport.subscribe(payload => {
-      if (payload.type === 'block') {
-        const model = payload.model;
-        if (
-          matchModels(model, [ListBlockModel]) &&
-          model.props.type === 'numbered'
-        ) {
-          const next = std.store.getNext(model);
-          correctNumberedListsOrderToPrev(std.store, model);
-          if (next) {
-            correctNumberedListsOrderToPrev(std.store, next);
+    const afterImportBlockSubscription = slots.afterImport.subscribe(
+      payload => {
+        if (payload.type === 'block') {
+          const model = payload.model;
+          if (
+            matchModels(model, [ListBlockModel]) &&
+            model.props.type === 'numbered'
+          ) {
+            const next = std.store.getNext(model);
+            correctNumberedListsOrderToPrev(std.store, model);
+            if (next) {
+              correctNumberedListsOrderToPrev(std.store, next);
+            }
           }
         }
       }
-    });
+    );
+
+    return () => {
+      afterImportBlockSubscription.unsubscribe();
+    };
   };