1080p playfield shows oversized dark band on left edge

[jeffdarcy]

Observed during public GitHub Pages testing on a 1080 monitor. The left side of the playfield can show a large dark vertical band / heavy left-edge darkness.

Evidence gathered locally against the same build path:

• Reproduced at http://127.0.0.1:5174/PILEUP/?scene=level&seed=public-1080-qa with a 1920x1080 viewport.
• Screenshot saved during investigation at /tmp/pileup-local-1080-wait.png.
• Public Pages URL is https://relic-forge.github.io/PILEUP/.

Likely cause:

• This appears to be rendered inside the Phaser canvas, not from GitHub Pages/CSS layout.
• DarknessSystem.renderVignette() intentionally paints side darkness, and syncScreenSurfaces() applies overscan/scale based on camera zoom.
• At the left edge of the world, that screen-space vignette combines with the camera-at-boundary composition and the darkness render texture, making the left side read as a large dark bar.

Files to inspect:

• src/systems/DarknessSystem.ts
• src/systems/CameraSystem.ts
• src/systems/ResponsiveScaleSystem.ts

Acceptance target:

• At 1920x1080 and typical 1080p browser chrome heights, the playfield should not show an obvious opaque left bar at spawn or while panning near the world edge.
• Preserve horror vignette/edge darkness, but keep it balanced and intentional across desktop1080 and smaller browser windows.