[Feature Request] Add per-game HDR-Like Inverse Tone Mapping mode toggle

[SaltyBet]

Your system information

• Steam client version: 1726683985
• SteamOS version: 3.5.19
• Opted into Steam client beta?: No
• Opted into SteamOS beta?: No
• Have you checked for updates in Settings > System?: Yes

Please describe your issue in as much detail as possible:

• Gamescope defaults to an SDR-like ITM mode for SDR games.
• Gamescope has an HDR-Like ITM mode (BT.2446 Method A).
• That HDR-Like ITM mode is hidden behind a set of command line switches.
• There is no way to toggle HDR-Like ITM mode per-game inside Gaming Mode.
• This is a Feature Request to add a per-game (be it Steam or Non-Steam) HDR-Like Inverse Tone Mapping toggle plus related options (SDR nits, Target nits).

Steps for reproducing this issue:

N/A