PR #265: Default secondary binding to None

PR #265

Title: Default secondary binding to None

Source PR: WinNative-Emu/WinNative#265
Source branch: fix-secondary-binding-none-default
Source commit: a6394594cf833262c11d4923e1c0178f3d5eace8
Build workflow run: https://github.com/MaxsTechReview/WinNative/actions/runs/24853286666

What This PR Is About

• Add None as the first option in keyboard, mouse, and gamepad binding picker lists.
• Keep secondary bindings that are unset from falling back to UP in the control editor.
• Preserve existing profile serialization by continuing to write the enum value NONE.

Attached Artifacts

• WinNative-Debug-Standard-PR.265-a6394.apk
• WinNative-Debug-Ludashi-PR.265-a6394.apk

Built from source commit a6394.