chore: import SwapKit UI into wallets

[towanTG]

Summary

• Import @swapkit/ui as a workspace package in the wallets repo.
• Replace the Vite playground with the UI widget playground and Cloud Run/CDN deployment assets.
• Bring over UI GitHub workflows, beta release lane, dependency update workflow, Cloud Build/Terraform config, and lefthook setup.
• Repoint package metadata and Cloud Build repository references from swapkit/ui / swapkit-ui to swapkit/wallets / swapkit-wallets.
• Sanitize .npmrc by removing committed npm token lines and keep only the ${NPM_TOKEN} placeholder.

Verification

• bun install --force
• bun build:ci
• bun lint (passes with existing UI complexity warnings in swapkit-widget-controls.tsx)
• bun type-check:ci
• pre-commit hook: lint + type-check

Follow-up Outside This PR

• Configure npm trusted publishing or token permissions for @swapkit/ui from swapkit/wallets.
• Recreate/repoint GCP Cloud Build repository resources/triggers to swapkit-wallets where needed.
• Rotate the npm token that was previously committed in .npmrc.