add reusable haptic engine and integrate core DeFi feedback flows

[EstebanCanales]

Overview

Integrated a haptic feedback engine in the Neko web app to provide tactile responses on key user interactions.

Motivation

Haptic feedback improves perceived quality on mobile browsers and PWA installs, helping Neko feel native, not only visually native.

What was implemented (Issue #198)

• Implemented a reusable useHaptic() hook for cross-feature usage.
• Added haptic triggers for:
  • wallet connect
  • transaction confirm
  • transaction error
  • swap execute (success/error)
  • vault deposit/withdraw (success/error)
• Added capability guards and graceful fallback:
  • respects prefers-reduced-motion
  • checks device/browser support
  • no-op on desktop/no-touch devices
  • silent no-op on unsupported environments

Scope decisions

• Implemented with native Web Vibration API via reusable wrapper/hook architecture.
• Centralized haptic patterns/constants to keep implementation clean and scalable.

Acceptance Criteria Mapping

• Hook implemented and documented
• Haptic fires on at least: tx confirm, tx error, wallet connect
• No effect on desktop (graceful no-op)
• Works on iOS Safari and Android Chrome in PWA mode

Demo video:

https://cap.so/s/zkz52amjy0fsmqd

[drips-wave]

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Issue	Title
#198	Haptic Engine Web Integration	Link to this issue

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