V2.2 improvements (#12)

* feat: advanced output actions and settings screen organization

- enhance settings UI with output handling options
- reorganize setting sections and captions
- improve collapsible sections

* refactor: segmentation loading and manually handle dicomseg files not indexed in dicomstore

* refactor: use shared QSettings instance

* fix: remove unused argument in _closeOtherSettingsSections

* refactor: extract widget names into a constant for better maintainability

* fix: add error handling for JSON and CSV file loading

* added log info which output file is loaded.

NOTE: we explicitly don't load all files but only the first one. The user can open any file through the Output tab.

* fix: add error handling for loading tabular output files

* fix: add error handling for label volume loading

* fix: improve error handling for terminology context loading

* Apply suggestions from code review

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

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Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: LennyN95