Fix: Skip Scenes in Queue That Have no File

[Gykes]

Description

This modifies up the queue system to check if a scene has a file, and if not, skip it from automatically playing when you have Continue playlist by default.

Fixing that issue brought up another issue of what happens when you click on a fileless scene within the queue. I went ahead and fixed it by checking for a file and then displaying a blank screen noting that this scene is fileless. I'm not 100% in love with this solution but I cant think of a much better one in the moment. Screenshot below.

Related Issue

closes #6814

Testing

Local dev env

Screenshots

Checklist

• I have read and understood the Contributing document.
• I have read and understood the AI Usage Policy document.
• I have made corresponding changes to the documentation (if applicable).

AI Usage Disclosure

• I have used AI tools to assist with this pull request, and I have disclosed the tools and how I used them below.

Drafted via Claude Opus. Refactored by myself.

Additional Context

Would like design input on the fileless screen. I think it's "functional" but I don't know if this is the best soloution.