Implement dynamic shared-file icon overlay in BrowserUI

[jochenwezel]

Summary

CompuMaster.Dms.BrowserUI currently distinguishes normal and shared file icons through two default ImageList indices:

• index 6: default document/file icon
• index 7: default shared document/file icon

These are wired in DmsBrowser.vb via:

_FileIcons = New SystemIconsImageListWrapper(Me.ImageListFileIcons, 6, 7)

The file list uses SystemIconsImageListWrapper.GetSIImageListIndexForFileExtension(FileExtension, file.ExtendedInfosIsShared), so shared file state is functionally relevant.

Current behavior

SystemIconsImageListWrapper.OverlaySharedIcon(source As Icon) is currently only a workaround:

'WORKAROUND: until fully implemented, just return the default shared icon
Return ImageToIcon(Me.SIImageList.Images(Me.DefaultSharedIconIndex))

As a result, shared files do not get a true overlay on top of their actual file-extension icon. Instead, shared files fall back to one generic default shared icon.

After fixing #12, DmsBrowser no longer deserializes a designer-generated ImageListStreamer. The initial ImageList is now constructed from normal embedded bitmap resources. During that change it became visible that there is no separate embedded iconfinder_Document... - Shared.png resource file in the project. The old designer stream apparently carried a pre-serialized image for index 7.

Desired behavior

Implement the shared-file marker dynamically instead of relying on a pre-rendered Document - Shared.png resource.

The desired approach is:

• keep index 6 as the normal default document/file icon
• create index 7 dynamically from index 6 plus a share overlay
• apply the same overlay logic to shell/file-extension icons returned by ExtractIcon
• avoid adding or shipping a separate Document - Shared.png file
• keep existing ImageList indices and keys stable for compatibility

Relevant code

• CompuMaster.Dms.BrowserUI/DmsBrowser.vb
  • constructs SystemIconsImageListWrapper(Me.ImageListFileIcons, 6, 7)
  • calls GetSIImageListIndexForFileExtension(..., file.ExtendedInfosIsShared)
• CompuMaster.Dms.BrowserUI/SystemIconsImageListWrapper.vb
  • GetSIImageListIndexForFileExtension
  • GetIconForFileExtension
  • GetIconFromDLL
  • OverlaySharedIcon
• CompuMaster.Dms.BrowserUI/Resources/sharing.png
  • likely candidate overlay artwork already available in the project

Acceptance criteria

• Shared files show their normal file-extension icon with a visual shared marker overlay.
• Files without shell/file-extension icons use a dynamically generated shared default document icon.
• No designer-serialized ImageListStreamer or binary WinForms object resource is reintroduced.
• No additional static Document - Shared.png resource is required.
• Existing ImageList keys/indices used by DmsBrowser remain compatible.
• Add or update tests where practical to verify the ImageList contains the default shared icon and that shared extension icons are added through the wrapper path.