Fix Data Grid Selection & Batch API Sync Bugs

You are maintaining an enterprise data grid component (DataGrid) that fetches products from /api/products, supports multi-row selection, batch updates, and page switching. Users report several subtle state synchronization and UI bugs during batch actions and navigation.

Reported Bugs

1. Stale Selection on Page Change & Refresh: When switching pages using the pagination buttons (Previous, Next) or clicking Refresh Data, selected items from the previous page remain selected in state, causing incorrect item counts in the batch summary bar (X items selected). Switching back to a page should clear previous selections unless re-selected.
2. Race Condition / Out-of-Order Select All: Clicking the master Select All checkbox selects items currently loaded in the page. However, if a user toggles Select All or individual items while a batch update request is pending or right after triggering a page change, the UI state becomes corrupted or out-of-sync with what is displayed.
3. Failed Batch Retry State & Partial Selection Discrepancy: When a batch API call (POST /api/products/batch-update) fails, the selected items should remain selected so the user can re-try. However, if the user modifies selection during an active batch update or after a failed batch update, clicking Apply Batch Action performs the action on an incorrect subset of items because the pending state is not reset or handled cleanly.

Requirements

• The initial fetch loads /api/products?page=1 (limit 5 per page).
• Display pagination buttons Previous and Next, along with page indicator text Page 1 of X and a Refresh Data button.
• Each table row has a checkbox (aria-label="Select row [ID]" or aria-label="Select item [Name]"). The table header has a master checkbox with aria-label="Select all rows".
• Selection state must be scoped to the currently displayed dataset. When the page changes or Refresh Data is clicked, row selections must be reset to empty.
• When items are selected, display a batch summary bar containing: text matching X selected (e.g. 2 selected), a dropdown select for status action (Set Status), and an Apply Batch Action button.
• Clicking Apply Batch Action sends a POST request to /api/products/batch-update with { ids: string[], status: string }.
• During batch submission, disable the Apply Batch Action button, Refresh Data button, and row selection checkboxes to prevent state race conditions. Display a loading message Updating....
• On batch action success, clear selections and refresh the current page dataset.
• On batch action error, show an error alert message Failed to apply batch action. Please try again. Keep the selected checkboxes intact so the user can retry, and re-enable inputs upon failure.