feat(timeline): shoreline water — wave texture, swash, foam, glints

Replace the current-ribbon water (read as decorative stripes, not water)
with a composition that treats the tide curve as a shoreline: a drifting
overlapping-arc wave texture (alternating teal/white rows, downward flow
plus sideways sway), two wide swash bands breathing along the curve, a
broken foam dash flowing down the water's edge, twinkling surface glints,
and a stronger right-side depth gradient. Bubbles and sheen stay. Tide
strength still scales speed, density, amplitude, and counts.

TideTimeline now computes the curve path once and passes curveD to
TideWater for the edge effects.

Constraint: tide curve stays static and crisp — all motion lives inside
the clipped fill; swash/foam strokes are centered on the curve so only
their inner half shows through the clip.
Confidence: high
Scope-risk: local
Reversibility: trivial
Directive: tune row spacing (ROW) and arc width (ARC) first if the
texture feels too dense or too sparse on real devices.
Tested: tsc build, vitest 11/11, Playwright zoomed screenshots in light
and dark themes at strength 100%.
Not-tested: real-device WebView frame rate with 4+ stacked sections.
Related: a8d8067, docs/superpowers/plans/2026-06-11-realistic-waves.md

🐙 Autopus <noreply@autopus.co>