OFXR Bridge V439, release 37

This release ports upstream V452's adaptive presenter pacing into the native
DLSS FG fork. On non-SteamVR runtimes, OFXR now adjusts when the game starts
its next frame based on whether generated images are actually ready. This
addresses cases where submission counters look healthy but the runtime
receives generated frames before the GPU has finished writing them.

Changes

• Readiness-based pacing in 2X and 3X. OFXR can release the game up to
  one display slot earlier at 2X or two at 3X. It evaluates 30 generated
  groups at a time and uses a cooldown before moving back to reduce latency.
  The learned position survives presenter restarts and is bounded when
  changing the multiplier.
• Safe admission for D3D11 and Vulkan bridges. The release target always
  belongs to an already queued group. This adapts the upstream change to
  avoid waiting for a future submission that the blocked game has not yet
  enqueued. Repeated frames cannot satisfy the sequence gate.
• Support for this fork's extrapolation order. Readiness follows the
  first actual synthetic image even when the real image is submitted first.
• New diagnostics. Flight-recorder event 802 reports release position,
  unwritten and early images, and adjustments. See
  diagnostics.

SteamVR retains its existing pacing and 3X delay. Native DLSS FG and the
Preset A / Performance Preset C selector from release 36 remain available.
Changing the NVIDIA model preset still requires restarting the game.

Based on djules75's V452 presenter fix, commit 006ac8d,
ported selectively rather than replacing the fork with upstream V452.
The package therefore retains the internal V439 identifier.

Validation

• Windows x64 Release build with native DLSS FG enabled.
• 120 automated regression tests passed, including new controller tests,
  D3D12 2X/3X interpolation and extrapolation, D3D11 admission, and a
  SteamVR control that verifies the new controller stays disabled.
• Native DLSS FG correctness tests passed under Preset A and Preset C.

No fresh Galactic Racer race or headset test was completed for this port;
the game-testing connection was unresponsive. The release 36 A/C race
measurements are separate evidence and are not a benchmark of this change.

Package and installation

The Windows x64 archive contains the tray, OpenXR and Vulkan layers,
benchmark, production NVIDIA DLSS-G runtime, documentation, and licenses.
The bundled NVIDIA runtime is unchanged; Preset C's updated model is
supplied separately by the NVIDIA app beta. SHA256SUMS.txt lists packaged
file checksums, and a separate checksum accompanies the ZIP.

Disable OFXR and close games using it before replacing an existing install.
Extract the archive and run OFXRBridgeTray.exe to enable it again.