feat(panel): cascading columns, WB colour swatches, stronger HDF glow

Layout
- the panel is a cascade of columns: the rail's tabs, the tab's chips, the
  open chip's sub-chips, then the ruler. A child column no longer hides the
  column it came from (TEMP -> COLOR TEMP keeps TEMP visible); chips stack one
  per row instead of wrapping
- FRAME's WATERMARK opens its own column, so the frame chips stay put
- CREATE RECIPES gets the wide column its two-up form needs

WB colour swatches
- the ruler draws a colour box under the slider that follows the value:
  COLOR TEMP is the Kelvin colour (Tanner Helland), TINT runs green -10 ->
  neutral 0 -> magenta +10

HDF EFFECT
- knee 0.55..0.85 -> 0.45..0.75, blur 0.004+0.015n -> 0.006+0.024n of the
  width, screen alpha 0.15+0.35n -> 0.28+0.52n: a wide halo on the highlights
  instead of a hairline glow. Web copy of toneShader only — the phone keeps
  its own tuning.

Tabs
- rail order is PRESETS, FAVORITED, WB, LIGHT, FX, FRAME, CREATE RECIPES

docker/frontend/src/engine/exportEngine.ts

@@ -375,10 +375,12 @@ export async function renderPhoto(input: RenderInput): Promise<RenderResult | nu
       drawBlurred(canvas, surface, width, height, (Math.abs(sharpKnob) / 10) * 3);
     }
 
-    // 5b. HDF bright-pass bloom.
+    // 5b. HDF bright-pass bloom. The web demo shows the effect off, so both the
+    // blur radius and the screen alpha push further than the phone's: a wide
+    // halo around the highlights instead of a hairline glow.
     if ((adjustments.hdf ?? 0) > 0) {
       const strength = (adjustments.hdf ?? 0) / 10;
-      const sigma = width * (0.004 + 0.015 * strength);
+      const sigma = width * (0.006 + 0.024 * strength);
       const { glowEffect: effect } = effects();
       const srcShader =
         paintShader ??
@@ -389,7 +391,7 @@ export async function renderPhoto(input: RenderInput): Promise<RenderResult | nu
         effect != null ? own(effect.makeShaderWithChildren(glowUniformArray(), [srcShader])) : null;
       const glowPaint = own(Skia.Paint());
       glowPaint.setBlendMode(Skia.BlendMode.Screen);
-      glowPaint.setAlphaf(0.15 + 0.35 * strength);
+      glowPaint.setAlphaf(0.28 + 0.52 * strength);
       if (glowShader != null) {
         glowPaint.setShader(glowShader);
         glowPaint.setImageFilter(