Offline proxies not handled

[in03]

Issue

If Resolve links to proxies but they then become unavailable, they're considered 'offline' by Resolve. This usually means Resolve has lost access (maybe disconnected network drive or removable media) or the proxies were deleted or moved elsewhere. Currently they're seen as 'linked' and so if all proxies are offline, the script will say "All proxies are linked" and exit.

Proposal

Create a handler specifically for offline proxies. Prompt the user if offline proxies are detected:

[Title] Offline proxies detected
[Body] 5 proxies are linked, but offline. Would you like to queue the offline clips anyway?
[Yes] [No] [Cancel]