Improve DmsBrowser file icon quality and row height

[jochenwezel]

Summary

The DMS Browser currently displays file icons in the file list with visibly reduced quality. In Details view the icons appear very small/pixelated, especially for shell-provided file-extension icons.

Observed in the WebDAV demo dialog: file rows are compact and the file-type icons look like downscaled low-resolution variants.

Current behavior

• DmsBrowser uses ImageListFileIcons for both ListViewDmsFiles.SmallImageList and LargeImageList.
• ImageListFileIcons currently appears to operate around a small 24 px icon size.
• SystemIconsImageListWrapper extracts shell icons via ExtractIcon, then normalizes through ImageToIcon to 24x24.
• In ListView Details view this results in poor visual quality and a cramped row height.

Desired behavior

Improve file icon rendering quality in the DMS Browser list:

• Prefer a Windows shell icon size suitable for Details view, likely 32x32 as a practical default.
• Evaluate whether 32x32 or 48x48 gives the best balance for Details view readability.
• Increase ImageListFileIcons.ImageSize accordingly.
• Increase ListViewDmsFiles row height implicitly via the assigned SmallImageList size, or explicitly if needed.
• Keep tree view icons usable; if necessary split file-list and tree-view image lists so folder tree row height does not become too large.
• Ensure the dynamic shared-file overlay scales with the chosen icon size instead of hardcoding 24x24.

Notes

Windows shell icons are commonly available through system image lists at sizes such as small 16x16, large 32x32, extra-large 48x48, and jumbo 256x256 depending on API. For this WinForms Details view, 32x32 is probably the safest first target; 48x48 may be too tall unless the browser intentionally wants a more spacious file list.

Acceptance criteria

• File icons in DmsBrowser Details view are noticeably sharper than the current small/downscaled rendering.
• Row height is increased enough that 32x32 icons are not clipped or visually cramped.
• Shared overlay rendering remains crisp and correctly positioned at the selected icon size.
• Existing ImageList indices/keys remain compatible where possible.
• Add/update BrowserUI tests where practical to assert the configured image size and shared overlay behavior.