New effect family "Fluido": real-time GPU fluid simulation (ink-in-water)

Stable-fluids solver (fluid.js) on ping-pong half-float framebuffers:
semi-Lagrangian advection, vorticity confinement (clamped — unbounded
confinement overflows half-float and kills the field), 22 Jacobi pressure
iterations, audio-driven dye/force splats. Three wandering emitters inject
palette-coloured dye (brightness-normalized so dark palette entries stay
vivid); bass drives injection and stirring, beats fire directional bursts,
treble adds swirl. Universal modifiers map onto the sim: warp = vorticity,
speed = sim speed (brightness is speed-normalized), sym = kaleidoscope with
a wedge that rotates via rotSpeed, contrast/invert on display.

The Visualizer delegates to FluidSim when the preset has isFluid (flag is
always present so Object.assign merges can't leave it stale). 102 new
presets (17 palettes x 6 variants).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/effects.js

@@ -33,7 +33,8 @@ const FAMILIES = [
   { name: 'Tri-Banda', scale: 1.0, bgDark: true },
   { name: 'Reattivo Bassi', scale: 1.0, bgDark: true },
   { name: 'Reattivo Medi', scale: 1.0, bgDark: true },
-  { name: 'Reattivo Alti', scale: 1.0, bgDark: true }
+  { name: 'Reattivo Alti', scale: 1.0, bgDark: true },
+  { name: 'Fluido', scale: 1.0, fluid: true }  // GPU fluid sim (fluid.js), not the uber-shader
 ];
 
 // Palettes: low colour (a) -> high colour (b), plus optional hue-cycle/sat.
@@ -88,7 +89,10 @@ function makeEffect(fi, pi, vi) {
     speed: v.speed,
     colorA: pal.a,
     colorB: pal.b,
-    bgDark: fam.bgDark ? 1 : 0
+    bgDark: fam.bgDark ? 1 : 0,
+    // Always present (0/1) so Object.assign merges in setEffect can't leave a
+    // stale flag behind when switching between fluid and shader presets.
+    isFluid: fam.fluid ? 1 : 0
   };
 }