Add Odin 3 HDR and compositor AutoHDR support

[enjihn]

Summary

Adds qualified native HDR support for the AYN Odin 3 internal OLED and optional compositor AutoHDR for SDR games.

• Qualify only the exact Odin 3 internal DSI-1 display
• Add Steam Display HDR and SDR-on-HDR brightness controls
• Add a global AutoHDR setting and per-game Performance QAM override
• Show the HDR badge only for native HDR or AutoHDR confirmed as rendered by Gamescope
• Keep Gamescope's dynamic limiter state in the user runtime directory so later-launched games honor Steam's FPS cap
• Preserve native HDR bypass and fail closed when hardware, compositor support, or runtime feedback is incomplete
• Keep external displays and unsupported devices outside the Odin 3 calibration policy

AutoHDR requests the Quality policy. Gamescope may use its internal Efficient path only as a rendering fallback.

Dependency

Depends on virtudude/armada-packages#13, which supplies the Gamescope HDR and AutoHDR patches plus Odin 3 8bpc output dithering.

The compositor and kernel changes are intentionally kept out of this repository.

Calibration

The internal display profile currently uses:

• 203 nits SDR reference white
• 650 nits target peak

These values are inherited and provisional. They have not been established through colorimeter measurement and are never applied to external displays.

Validation

• 71 frontend tests
• 28 backend tests
• 12 production policy tests
• TypeScript type checking
• Gamescope capability-gate tests
• Conflict-free merge preview against current main
• Combined Release 11 image build
• Live Odin 3 testing of native HDR, AutoHDR, per-game control, contextual HDR feedback, and the dynamic frame limiter

Fresh-install acceptance remains in progress, so this PR is a draft.