v0.10.3 (beta) — Brightness, vignette and a setup fix

A beta, published as a GitHub pre-release: setup's release list and "latest" do not
offer it, so existing installations stay on v0.10.2 unless you install this one on purpose.
To try it, download this release's setup for your platform and run it; it installs its own
bundled version.

Changes

• Brightness slider (#44).
  Display → Picture in the launcher and the in-game overlay (F1), 50-200, default 100. It
  brightens or darkens the mid-tones on top of the game's own brightness curve; black and white
  stay as they are, and 100 is the picture as before. Applies as you move it.
  [display] brightness in settings.ini, or RECOMP_BRIGHTNESS.
• Vignette off, or weaker (#47).
  The darkened screen edges the venues draw can be turned off (Vignette), or faded toward the
  undarkened picture (Vignette strength, 0-100%). Both apply at once. [display] vignette and
  vignette_strength, or RECOMP_VIGNETTE / RECOMP_VIGNETTE_STRENGTH.
  How both work.
• Windows setup no longer stops on "Access is denied … status.txt"
  (#40). The wizard's progress
  file could be locked while setup replaced it, and one refusal stopped the whole installation
  (WinError 5). Progress updates are now best effort: a refused one keeps the previous text
  and setup carries on. The wizard also reads the file in a way that no longer blocks the
  replace. The fix is in the setup itself, so it helps from this release's setup onward.
• For developers. regress.py --only picture drives the launcher's new controls end to end;
  scenario_suite.py --settings accepts brightness, vignette and vignette_strength.

Validation

• macOS (Apple Silicon): full regression 18 of 18 on the feature branch (the golden frames and
  the pinned fight replay are unchanged, so the defaults leave the picture and the game as
  before). Five repeatable fights measured each picture setting: vignette off lifts the
  darkened edges with the centre unchanged; strength 50 lands on the predicted blend; brightness
  150 lifts the mid-tones. A read-back of the window confirms brightness on screen.
• Setup: the new status tests fail on the old code and pass now; on hosted Windows, two tests
  hold the file with real Windows handles while setup writes to it.
• Hosted CI builds and tests Windows (MSVC, including the game-side sources), macOS and Linux.
• Not yet play-tested on the Steam Deck or Windows — that is what this beta is for.

Known limits

• The vignette options were measured in the default One on One venue; other venues and Story
  scenes were not toured one by one.
• The earlier limits remain (scene loads, the Deck at render scale 3, Windows shader compiles,
  the intermittent audio-queue gate); see known issues.

Updating

Download this release's setup for your platform and run it, choosing your existing
installation to update it. Setup builds the game locally from your own dump and preserves
player data. Your choices go into settings.ini as before; the three new settings start at
the values that keep the picture unchanged.