[WC-3355]: fix combobox not updating displayed value on external attribute change

[rahmanunver]

Pull request type

Bug fix (non-breaking change which fixes an issue)

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Description

In database mode, the combobox displayed a stale value when the target attribute was changed externally (e.g. by a popup combobox writing to the same attribute).

Root cause: DatabaseSingleSelectionSelector.updateProps() only synced currentId on initial load (!this.currentId). When the attribute changed from value A to value B while currentId was already set to A, the condition was false so currentId stayed at A and the display never updated.

Fix: Added a second condition — also enter the sync branch when the current option's stored value no longer matches the incoming targetAttribute.value, using the existing _valuesIsEqual helper for type-safe comparison. A matching value short-circuits the scan, so there is no performance impact on the common (no-change) case.

Files changed:

• src/helpers/Database/DatabaseSingleSelectionSelector.ts — core fix (one condition added)
• CHANGELOG.md — ### Fixed entry under ## [Unreleased]
• package.json + src/package.xml — version bump 2.8.0 → 2.8.1
• AGENTS.md — architecture reference for future debugging sessions

What should be covered while testing?

1. Open a page with two comboboxes in database mode bound to the same attribute on the same object.
2. Select a value in combobox A (e.g. "Option 1").
3. Open a popup that contains combobox B; select a different value (e.g. "Option 2") and close the popup.
4. Expected: Combobox A now displays "Option 2".
5. Before fix: Combobox A still shows "Option 1" (stale).
6. Verify the reverse direction: change in A after changing via B also works correctly.

[r0b1n]

We bump versions in release preparation step nowadays