Fixes: #18943 ## Problem Two bugs related to the Files field: 1. **File loss on click outside**: When `MultiItemFieldInput` was not in edit mode (input hidden), clicking outside would still call `validateInputAndComputeUpdatedItems()` with an empty `inputValue` and `itemToEditIndex = 0`, causing the first file to be silently deleted. <img width="624" height="332" alt="image" src="https://github.com/user-attachments/assets/657aff2c-e497-4685-b8b7-fa22aba772f8" /> 2. **Unsigned file URLs in timeline activity**: FileId, FileName stored in `timelineActivity.properties.diff` (before/after values) were not being signed (timeActivity.properties is stored as json in database), making them inaccessible from the frontend. <img width="1092" height="103" alt="image" src="https://github.com/user-attachments/assets/23d83ea3-4eb9-41ef-a99c-c4515d1cfb35" /> ## Reproduction https://github.com/user-attachments/assets/e75b842b-5cbb-46e8-a923-ac9df62deb98 ## Changes - `MultiItemFieldInput.tsx`: Wrap the validate + onChange logic in `if (isInputDisplayed)` so it only runs when the input is actually open. - `timeline-activity-query-result-getter.handler.ts`: New handler that iterates over `properties.diff` fields and signs any file arrays found in `before`/`after` values (call same method: `fileUrlService.signFileByIdUrl` as table field view `FilesFieldQueryResultGetterHandler`. - `common-result-getters.service.ts`: Register the new handler for `timelineActivity`. ## After https://github.com/user-attachments/assets/368c7be1-3101-43a2-ac93-fe1b0d8a7a37