Create Playwright Unit Tests for Grid-Store Interactions

Objective: Create a new Playwright unit test suite (test/playwright/unit/grid/StoreInteractions.spec.mjs) to verify the interaction between the GridContainer (specifically GridBody) and its Store during runtime data mutations.

Scope: The tests must verify that the Fixed-DOM-Order architecture is maintained during dynamic data changes. We expect minimal deltas (content updates only, no row reordering/insertion/removal) for operations that fit within the existing row pool.

Key Scenarios to Test:

1. Runtime Insert (store.add / store.insert):

   • Insert a record at the top (index 0).
   • Verify: Visible rows should update their content (shifting data down).
   • Assert: ZERO structural deltas (moveNode, insertNode) for the rows themselves. Only content (innerHTML, text) and style (transform) updates.

2. Runtime Remove (store.remove):

   • Remove a visible record.
   • Verify: Remaining rows shift up (content update).
   • Assert: ZERO structural deltas. Unused rows at the bottom of the pool should be hidden or cleared, not removed from DOM.

3. Runtime Sort (store.sort):

   • Trigger a sort operation.
   • Verify: Rows display records in the new order.
   • Assert: ZERO row moves. The physical DOM rows should remain in place; only their content changes.

4. Runtime Filter (store.filter):

   • Apply a filter that reduces the dataset.
   • Verify: Visible rows update.
   • Assert: Correct number of rows are visible. Excess rows in the pool are hidden (e.g., display: none or empty content), NOT removed from DOM.

Technical Details:

• Use captureDeltas helper (similar to Pooling.spec.mjs) to inspect VDOM actions.
• Ensure Neo.config.useVdomWorker is false to test logic synchronously.
• Mock ResizeObserver and DomAccess as needed.

Why: To ensure that standard store operations do not break the high-performance rendering strategy of the new Grid implementation.