surf_flow

The surf part's game-state pass, registered at priority 110 — after surf_ink, before the fade. Six effects, each behind its own property so the part can drive them from gameplay:

• bloom — a single-pass ring of 12 luminance-thresholded taps, soft-added.
• speed_lines — broken radial dashes near the frame rim, each segment on its own flicker clock, reading as rushing air.
• flash — whole-frame whitening for the storm hits.
• hue_pulse — a slow breathing hue rotation as flow heats up.
• fade — desaturates and darkens as the board goes under.
• vignette — the constant radial darkening.