fix(ripple-button): clean up overlapping ripples independently

[xpeng5278-web]

Fixes #1019

Summary

Fixes the RippleButton cleanup backlog: each new click was canceling the previous ripple's removal timer, so expired nodes accumulated during rapid clicks and then drained one-per-duration after input stopped.

What

• Replaces the array-wide "latest ripple only" useEffect timeout with a small internal Ripple child that owns its own cleanup timer and calls a stable removeRipple(key) callback.
• Adding or removing a different ripple no longer resets other ripples' lifetimes; unmount clears each outstanding timer.
• Uses a monotonic key instead of Date.now() so rapid clicks in the same millisecond do not collide.
• Regenerates apps/www/public/r/ripple-button.json and apps/www/public/llms-full.txt via pnpm build:registry.

Why

With default duration="600ms", click at t=0 and t=100 ms: both animations finish by t=700 ms, but main retained 1 node. Twenty clicks spaced 100 ms apart left 19 expired nodes after one more duration. #909 fixed missing --duration for animation; cleanup scheduling was unchanged.

How tested

Against unmodified main (cdb348cb):

• single click → 0 after 601 ms (pass)
• two clicks 100 ms apart → retained 1 after 601 ms (fail)
• twenty clicks 100 ms apart → retained 19 (fail)

With this branch:

• single click removes after duration
• overlapping clicks: first gone at t=601, both gone at t=701
• twenty rapid clicks leave 0 after another 601 ms
• unmount clears outstanding timers (vi.getTimerCount() === 0)
• consumer onClick still fires once per click

Repo gates:

• pnpm check (lint, typecheck, format:check, registry-deps:check) ✅
• pnpm build:registry ✅
• pnpm build ✅

Notes

Distinct from #908/#909 (animation duration CSS variable). No changes to the background Ripple component or button styling API.

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[Yeom-JinHo]

@xpeng5278-web
Thanks for the fix and the thorough repro! Confirmed the behavior locally.

I pushed one small commit on top (2b2a676) renaming the internal Ripple component to ButtonRipple to avoid confusion with the exported Ripple background component. No behavior change.