Implement #27869: Recall transpose options

[prodoelmit]

Resolves: #27869

• Stores TransposeOptions as static variable of TransposeDialog.
• When applying transpose, saves used options to that static variable
• Only applies to mode, direction and interval (there is more complex logic in initialization for other fields)

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[avvvvve]

I don't know if this is included in "other fields" as mentioned in the issue description (can you confirm @prodoelmit?), but it would be nice if the nested radio buttons maintained their state.

To reproduce:

1. In the 'To key' section, change the key and select 'Down' as the direction, then run the transposition.
2. Reopen the dialog and see that both the dropdown and radio button are recalled correctly.
3. Change to 'By interval' and transpose again.
4. Reopen the dialog. Now, in the 'To key' section, the last key chosen is still recalled, but the radio button has been reset to the first option ('Closest').

I'd expect the 'Down' radio button to still be selected.

Screen.Recording.2025-12-01.at.11.26.12.AM.mov

[avvvvve]

Looks good now!