fix(frame): add widget end inset for edge widgets when Frame is enabled

[ultherego]

Description

When Frame is enabled, edge widgets on both ends of the bar had no inset from the frame corners — _frameLeftInset/_frameRightInset (horizontal bar) and _frameTopInset/_frameBottomInset (vertical bar) fell back to 0 when no adjacent bar was present, causing widgets to sit flush against the frame.
Fixed by introducing _frameEndInset = frameThickness + frameBarEndInset as the fallback value. Also added a Widget End Inset slider in Settings → Frame → Border (default 0, range 0–20px) so users can add extra padding on top of frameThickness.

Type of change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that changes existing behavior)
• Refactor / internal cleanup
• Documentation
• Other

Related issues

Fixes #2597

Screenshots / video

Checklist

• My code follows the conventions in CONTRIBUTING.md
• I have tested my changes locally
• New user-facing strings are wrapped in I18n.tr() with translator context, reusing existing terms where possible
• Go changes: ran make fmt, added/updated tests, make test passes, and go mod tidy is clean
• QML changes: ran make lint-qml with no new warnings
• I have opened a corresponding pull request in dlx-docs to document any new behaviors: https://github.com/AvengeMedia/DankLinux-Docs

[Purian23]

Thanks for putting this together.
Couple things here, I think starting at 0 should be nearly edge to edge as some people will want the overlap. Then you can set a default wherever it lines up to the frame corners as it is now.

It breaks entirely when adding a 2nd or 3rd bar and becomes unresponsive. Removing the bars doesn't reload it and it stays unresponsive until dms restart. These are some of the items I was telling you were tricky that takes a bit more implementation to get correct.

Also the click targets are pretty far off on each end. Some may prefer it, but the defaults should work on the launcher button for example.

I am also in a refactor of the entire frame currently, but this would be a good addition once everything is worked out.

[ultherego]

Thanks for taking a look. In that case, it makes sense to wait for the Frame refactor — this commit can serve as a reference for the future implementation, as you mentioned. I'll close this PR for now and revisit once the refactor is done.

[Purian23]

Closing this out as I implemented in another direction via: ad32af6 - Though to note, sometimes framemode can still set incorrectly on the live switch from Standalone to Framemode, I could not fully nail it down. But now we have dedicated setting options in every mode to mitigate.

Thanks for the assist!