Perf/performance improvements

[epalosh]

[0.2.0] — Head-tracking feel + game-contention performance

Added

• Global hotkey (default F10) to toggle inference on/off entirely.
  Disabling stops MediaPipe (frees CPU) and snaps the in-game view to
  center; re-enabling resumes from the last calibration (no recenter).
  Rebindable in Settings → Hotkeys.
• Pause preview button — stops the camera-preview rendering (a
  diagnostic to measure its CPU cost) while tracking and the fps/inference
  readout keep running.
• CPU-contention controls so tracking holds up while a game saturates the
  CPU:
  • Window-visibility gating — preview frames + pose updates are skipped
    while the window is minimized / hidden to tray (tracking + game output
    continue).
  • OpenCV thread-pool cap (default 2) on the per-frame cvtColor / resize /
    decode work.
  • Optional Reserve CPU cores mode (Settings → Performance) pinning the
    process to the top logical CPUs so MediaPipe stays off the game's
    cores. Off by default; experimental.

Changed

• Default yaw mapping is now the soft-center curve at 3x sensitivity
  (fine control near forward view, fast swing to the apex). Pitch and roll
  keep the gentle linear default.
• Sensitivity sliders now range 0–5x (was 0–3x).
• Settings → Performance simplified — the raw "inference downscale" spinbox
  is gone (driven by the preset), and the OpenCV thread cap is not
  surfaced.
• Camera preview shows an explicit "tracking disabled" banner when
  inference is toggled off, instead of the misleading "no face detected".
• Reworded a setup-wizard tip ("Constant motion can be disorienting!").

Fixed

• Process priority was never actually raised to HIGH on 64-bit Windows —
  the ctypes SetPriorityClass call mis-marshalled the process handle
  and failed silently. Now set via psutil, so OpenFOV runs at HIGH and
  stops losing scheduler contests with the game's render thread.
• Shutdown crash ('Event' object is not callable): the camera-reader
  thread's stop Event shadowed threading.Thread._stop, so every exit
  threw and skipped pipeline cleanup. Renamed the attribute.

Packaging

• Bundle MediaPipe's libmediapipe.dll (~27 MB). It's loaded via dlopen
  at runtime, so Nuitka never saw it and --include-package-data skips
  DLLs — the standalone imported MediaPipe fine but the tracker failed to
  initialize ("Could not find module libmediapipe.dll").
• Bundle NPClient64.dll + TrackIR.exe. Nuitka's --include-data-dir
  silently skips .dll/.exe, so the installed app couldn't deliver
  tracking to iRacing (the registry pointed at a missing DLL).
• bundled_bin_dir() now detects a Nuitka build (__compiled__) so it
  resolves <exe>/resources/bin instead of over-shooting to dist/.
• Installer output renamed to OpenFOV-<ver>-setup.exe to match the
  release workflow, the winget manifest, and the docs.

Tests

• Full suite: 158/158 passing.