Sync Custom Start Degree with Numbering Position

[seanalexander]

Summary:
This PR introduces a feature that automatically synchronizes the Custom Start Degree field with the Numbering Position. When a user selects a numbering position (Top, Left, Right, Bottom), the corresponding angle (0, 90, 180, 270 degrees) is automatically set in the Custom Start Degree input, ensuring consistent behavior between the two options.

Changes:

• Added logic to update Custom Start Degree based on the selected Numbering Position if no custom degree is manually set.
• Numbering Position angles:
  • Top: 90 degrees
  • Left: 180 degrees
  • Right: 0 degrees
  • Bottom: 270 degrees
• Custom Start Degree remains flexible and can be overridden by the user if needed.

Impact:

• Improves usability by ensuring that the Custom Start Degree automatically reflects changes made via Numbering Position selection.
• Prevents confusion by keeping the two options synchronized while preserving manual overrides when necessary.

Testing:

• Tested functionality where selecting different Numbering Positions correctly updates the Custom Start Degree.
• Confirmed that manually setting Custom Start Degree still works as expected, overriding the numbering position when needed.

[leechwort]

Hi! Thank you for your contribution, I will check your PR asap!

[leechwort]

Hi @seanalexander! I'm testing your PR on my side, here is what I've got.
Settings "Top", "Left" and "Bottom" work fine:

Top	Left	Bottom

Setting "Right" looks weird:

Can you check this on your side? Here are screenshots of all settings:

s1	s2	s3

My inkscape version: Inkscape 1.3.2 (1:1.3.2+202404261509+091e20ef0f) on linux.