Code Quality: Improved app startup routine 2

[d2dyno1]

Resolved / Related Issues

• Were these changes approved in an issue or discussion with the project maintainers? In order to prevent extra work, feature requests and changes to the codebase must be approved before the pull request will be reviewed. This prevents extra work for the contributors and maintainers.
  Closes #issue...

Validation
How did you test these changes?

• Did you build the app and test your changes?

[yaira2]

@d2dyno1 what's the plan for this PR?

[d2dyno1]

I'm going to continue work on it this Thursday 🙂

[d2dyno1]

Ready for review!

[0x5bfa]

Great! in terms of codebase quality.

I understand as follows

• Update app UI thread initialization stage
• Rename ImageModel to Image
• Add a service for pinning/unpinning
• System.IO to SystemIO (FYI, I introduced this simpified namespace alias to see all reference to that namespace because this namespace reference in storage class is not favorable)

[hishitetsu]

This appears to prevent launch from a cached instance from working. When I try to launch the app again, the window does not appear.

[yaira2]

Should we revert?

[hishitetsu]

Before we revert, I first want to figure out how to make launching from the cached instance work again.

[hishitetsu]

Hmmm, even when I get the window to show up, the tabs don't show up properly or the app crashes.
If it is not required for the V3 release, it would be better to revert it once and test it after the V3 release.