fix: create new Position/Selection objects for scroll restoration

- Replace direct selection assignment with new Position/Selection objects
- Ensures proper transfer of cursor position between editor instances
- Fixes issue where cursor would jump to start of file after closing diff view
- Updated tests to properly mock Position and Selection constructors

src/integrations/editor/DiffViewProvider.ts

@@ -227,8 +227,13 @@ export class DiffViewProvider {
 		await new Promise((resolve) => setTimeout(resolve, 50))
 
 		// Restore the cursor position and scroll position from the diff view
-		// First set the selection to where the cursor was
-		editor.selection = selection
+		// Create new Position/Selection objects instead of direct assignment to ensure proper transfer
+		if (selection) {
+			editor.selection = new vscode.Selection(
+				new vscode.Position(selection.anchor.line, selection.anchor.character),
+				new vscode.Position(selection.active.line, selection.active.character),
+			)
+		}
 		// Then reveal the range to ensure it's visible
 		if (selection && !selection.isEmpty) {
 			// If there's an actual selection, reveal it
@@ -457,8 +462,13 @@ export class DiffViewProvider {
 				await new Promise((resolve) => setTimeout(resolve, 50))
 
 				// Restore the cursor position and scroll position from the diff view
-				// First set the selection to where the cursor was
-				editor.selection = selection
+				// Create new Position/Selection objects instead of direct assignment to ensure proper transfer
+				if (selection) {
+					editor.selection = new vscode.Selection(
+						new vscode.Position(selection.anchor.line, selection.anchor.character),
+						new vscode.Position(selection.active.line, selection.active.character),
+					)
+				}
 				// Then reveal the range to ensure it's visible
 				if (selection && !selection.isEmpty) {
 					// If there's an actual selection, reveal it

src/integrations/editor/__tests__/DiffViewProvider.spec.ts

@@ -78,9 +78,21 @@ vi.mock("vscode", () => ({
 		Eight: 8,
 		Nine: 9,
 	},
-	Range: vi.fn(),
-	Position: vi.fn(),
-	Selection: vi.fn(),
+	Range: vi.fn((startLine, startChar, endLine, endChar) => {
+		if (typeof startLine === "object" && typeof startChar === "object") {
+			return { start: startLine, end: startChar }
+		}
+		return {
+			start: { line: startLine, character: startChar },
+			end: { line: endLine, character: endChar },
+		}
+	}),
+	Position: vi.fn((line, character) => ({ line, character })),
+	Selection: vi.fn((anchor, active) => ({
+		anchor,
+		active,
+		isEmpty: anchor.line === active.line && anchor.character === active.character,
+	})),
 	TextEditorRevealType: {
 		InCenter: 2 as any,
 		InCenterIfOutsideViewport: 1 as any,