Move camera configuration code into a dedicated gui/camera_config package and extract UI construction into a new ui_blocks module. Renamed camera_config_dialog.py and camera_loaders.py to camera_config/camera_config_dialog.py and camera_config/loaders.py respectively, replaced the large _setup_ui implementation with setup_camera_config_dialog_ui(dlg) from ui_blocks.py, and added ui_blocks.py to build the dialog UI. Updated relative imports in __init__.py, main_window.py, and affected modules/tests to the new paths. This refactor improves modularity and keeps the dialog file focused on logic rather than bulky widget construction.

Move camera identity utilities into cameras.factory (apply_detected_identity, camera_identity_key) and add CameraSettings.check_diff for concise settings diffs. Major refactor of CameraConfigDialog: reorganize UI/state helpers, probe/preview lifecycle, auto-apply pending edits, improved scan/probe cancellation and dialog reject handling, duplicate-camera checks, add reorder/add/remove safety, and split preview helpers into a new preview module; also remove unused cv2 import. These changes centralize identity handling, improve preview & probe UX, and add safer settings application and logging. Tests updated to match the new contracts.

Add a unified _on_close_cleanup and closeEvent to ensure preview/worker shutdown and UI reset on dialog close/cancel. Make cleanup idempotent with a _cleanup_done guard, shorten worker wait times to reduce UI freeze, and defensively reset scan UI widgets. Connect scan cancel button handler. Initialize _multi_camera_settings fallback, tighten type annotations, and note eventFilter UI assignments. Refactor form/apply flow to build a new CameraSettings model, compute diffs, replace the working camera entry and update the active list item (apply now returns a truthy value). Call _reconcile_fps_from_backend when loading settings, remove exc_info from a loader error log, and invoke cleanup before accepting the dialog. These changes improve robustness during shutdown and reduce UI hangs.

Move preview state and session datatypes into preview.py and refactor low-level image ops into MultiCameraController static methods. preview.py now delegates rotation, crop, resize and pixmap conversion to MultiCameraController (with proper type hints and QTimer usage). loaders.py removes duplicate PreviewState/PreviewSession definitions and cleans imports. camera_config_dialog uses getattr to safely read backend.actual_fps and updates imports to match the refactor. MultiCameraController gains apply_rotation/apply_crop/apply_resize/ensure_color_* and to_display_pixmap utilities (default: no upscale when resizing).

Adapt camera config GUI tests to the refactored preview API: import PreviewState and replace checks against legacy dialog attributes (_loader, _preview_active, _preview_backend, _preview_timer) with dialog._preview.loader, dialog._preview.state (using PreviewState.*), dialog._preview.backend, and dialog._preview.timer. Update waitUntil conditions and assertions across test_cam_dialog_e2e.py to reflect the new preview state machine and object structure.