buildspec: Update obs-deps to 2025-07-11 & OBS 31.0.4

[Trouffman]

Description

buildspec: Update obs-deps to 2025-07-11
buildspec: Use OBS 31.0.4 - Replace/cancel PR #149
CI: Fix macOS SDK detection

Motivation and Context

Fix the MacOS SDK detection by using OBS 31.0.4.
Use 2025-07-11 OBS deps (used by OBS 31.1.1).
Prepare for OBS 31.1.1 usage in the template-plugin

This is a contribution in hope of getting back to a working plugin-template with some of the latest update.
Most of the changes have been from looking at the OBS repo and trying to identify changes. I might have missed some subtle changes.

How Has This Been Tested?

Still in pre-release / PR on DistroAV plugin

Types of changes

Bug Fix : complete macOS SDK detection fix from #145
Update clang script & requirements
Update Github actions for project build

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.

[PatTheMav]

Please use the PR template correctly:

• Write fully-worded summaries as "Description" and "Motivation and Context", not just bullet points
• Don't open a pull request if these changes have not even been tested yet
• Don't change the format of the "Types of changes", remove/uncomment the variants that don't apply and keep the ones that do apply
• The checklist is not a "nice to have" - if you cannot check all checkboxes, you should not open a PR in the first place.

The changes themselves are probably correct, but I will not look at them further before the PR template is correctly filled out and the checklist is completed.

[PatTheMav]

@Trouffman No need to close this, please just update the opening post accordingly.

If the plugin template builds correctly on your local system (and OBS loads the template plugin) that is sufficient testing.

Split up your changes into multiple commits with appropriate commit messages and then you should be able to complete the checklist. You can fix those things via a force-push to the same branch.

Please also include the fix to use ENABLE_FRONTEND instead of ENABLE_UI as discussed in obsproject/obs-studio#12382.

[RytoEX]

Superseded by #151.