refactor(editor): move focus block commands to blocksuite/shared (#10671)

blocksuite/affine/shared/src/commands/selection/focus-block-start.ts

@@ -0,0 +1,23 @@
+import {
+  type BlockComponent,
+  type Command,
+  TextSelection,
+} from '@blocksuite/block-std';
+
+export const focusBlockStart: Command<{
+  focusBlock?: BlockComponent;
+}> = (ctx, next) => {
+  const { focusBlock, std } = ctx;
+  if (!focusBlock || !focusBlock.model.text) return;
+
+  const { selection } = std;
+
+  selection.setGroup('note', [
+    selection.create(TextSelection, {
+      from: { blockId: focusBlock.blockId, index: 0, length: 0 },
+      to: null,
+    }),
+  ]);
+
+  return next();
+};