Fix non-reorderable table display order after topology changes

[Anujgiri1279]

#9570
Non-reorderable tables could display columns in the wrong order after columns were inserted or appended. Stale or duplicate DisplayOrder values from table reconciliation and settings loading were being sorted even though non-reorderable tables should always follow declaration order.

Changes

• Reset DisplayOrder to the column index for non-reorderable tables.
• Rebuild DisplayOrderToIndex to match that order.
• Preserve the existing sorting and compaction behavior for reorderable tables.

The change is limited to imgui_tables.cpp, inside ImGui::TableFixDisplayOrder().

Validation

• Built examples/example_null successfully.
• Ran example_null successfully through 20 frames.
• Built with WITH_EXTRA_WARNINGS=1 successfully.
• CodeQL reported 0 alerts.
• Secret scan found no secrets.

[ocornut]

Hello,

Thanks for your PR.

The dedicated Dear ImGui test engine was not included in this repository, so a focused imgui_test_suite regression test could not be run here.

The fix may or not be wrong, I don't know yet. But that's not an acceptable statement. Don't let Copilot state stupid things and submit that as PR. Use common sense.

[Anujgiri1279]

The fix may or not be wrong, I don't know yet. But that's not an acceptable statement. Don't let Copilot state stupid things and submit that as PR. Use common sense.

Yeah , Okay Understood

[ocornut]

Fixed by 68bd43b (#9570)