Set startup task priority above normal

[onehoon]

Summary

• Set the Addon-owned Task Scheduler startup task to explicit priority 2 (Above Normal) when it is newly created or legitimately recreated.
• Keep RunLevel = 0, interactive-token logon, --background, battery-safe settings, and no execution time limit unchanged.
• Keep priority out of OwnedStartupTaskState and IsCompliant, so an existing materially compliant task is not rewritten or elevated solely for this tuning.
• Add focused source-contract coverage for the priority value and the absence of Runtime process-priority mutation.

Validation

• dotnet build SteamInputAddonforClaw.slnx -c Debug --no-restore — passed, 0 warnings, 0 errors.
• dotnet build SteamInputAddonforClaw.slnx -c Release --no-restore — passed, 0 warnings, 0 errors.
• dotnet test tests/SteamInputAddonforClaw.Tests/SteamInputAddonforClaw.Tests.csproj -c Release --no-build — passed, 2,752/2,752.
• git diff --check — passed.

Scope and limitations

• Full1902 lifecycle, controller authority, update behavior, Task Scheduler trigger timing, RunLevel, and repair/UAC policy are unchanged.
• Windows Task Scheduler recreation and physical MSI Claw cold-logon, restart, and sleep/resume validation were not run in this environment.