Add Xbox360 rumble inactivity safety stop

[onehoon]

Summary

• Add a 5-second inactivity safety stop to the presentation-scoped Xbox360 rumble feedback bridge.
• Treat an explicit 0/0 callback as an immediate physical stop and cancel any pending delayed stop.
• Refresh the safety-stop deadline for each newer non-zero callback and cancel pending work during Dispose.
• Preserve the existing Xbox360 motor mapping and 8-bit-to-16-bit expansion.

Scope

• Reuses the existing presentation-scoped callback adapter and physical rumble sink.
• No VIIPER, authority, PID lifecycle, HidHide, descriptor, HID format, or SteamDeck behavior changes.
• The production default remains 5 seconds; tests inject short delays through the existing TryArm seam.

Validation

• dotnet build SteamInputAddonforClaw.slnx --configuration Debug --no-restore — passed, 0 warnings, 0 errors.
• dotnet build SteamInputAddonforClaw.slnx --configuration Release --no-restore — passed, 0 warnings, 0 errors.
• dotnet test tests/SteamInputAddonforClaw.Tests/SteamInputAddonforClaw.Tests.csproj --configuration Release --no-build --no-restore — passed, 2,725/2,725, 0 failed, 0 skipped.
• git diff --cached --check — passed.

Manual validation

• Physical MSI Claw/Xbox360 feedback validation was not performed in this environment. It remains required before closing the hotfix: sustained non-zero feedback must stop after 5 seconds of silence, explicit 0/0 must stop immediately, and a newer non-zero callback must keep the motor active until its refreshed deadline.