ComboBox Display Fix and BigData Grid Example Enhancement

Is your feature request related to a problem? Please describe.

1. ComboBox Initial Display Issue: Following the implementation of lazy record instantiation, Neo.form.field.ComboBox instances failed to display their initial value when the associated store contained raw data (e.g., arrays of strings or numbers). The input field would appear blank until the picker was opened, which would then trigger record instantiation.
2. BigData Grid Example Scope: The examples/grid/bigData demo, while showcasing large datasets, did not fully push the limits of column count, which is also a significant factor in grid performance.

Describe the solution you'd like

This feature addresses the ComboBox display issue and enhances the examples/grid/bigData demo to provide a more comprehensive performance testing ground.

1. ComboBox Initial Display Fix:

   • The Neo.form.field.ComboBox#updateInputValueFromValue method has been enhanced to correctly display the initial value even when the store contains raw data. It now intelligently handles Neo.data.Record instances, primitive values (strings/numbers), and raw data objects, ensuring the input field is populated as expected.

2. BigData Grid Example Enhancement:

   • The examples/grid/bigData/MainStore.mjs has been updated to include control options for 200 columns, allowing for testing with up to 100,000 rows * 200 columns = 20,000,000 cells. This provides a more extreme test case for grid rendering and scrolling performance.

Describe alternatives you've considered

(No specific alternatives considered as these are direct fixes and enhancements.)

Additional context

The ComboBox fix ensures a better user experience by correctly displaying pre-selected values in fields backed by lazily instantiated stores. The enhanced BigData grid example provides a valuable tool for benchmarking and optimizing grid performance under very high load conditions, particularly relevant for VDom reconciliation and rendering with a large number of columns.

ComboBox Fix Implementation:

• src/form/field/ComboBox.mjs#updateInputValueFromValue was modified.

BigData Grid Example Enhancement:

• examples/grid/bigData/MainStore.mjs was updated to include new column options.