fix: [WPN-29] Remove top-level await in crypto.ts

[draphy]

Issues

Fixes #60

Description

Removed top-level await in crypto.ts that caused failures in bundlers and runtimes that don't support it (e.g., Convex). Converted to lazy initialization pattern.

Also includes:

• Input validation for VAPID keys, subscription fields, payload size, and TTL bounds
• Payload padding edge case fix
• CLI simplified to use subcommands (npx @pushforge/builder vapid)
• npm publishing migrated to OIDC trusted publishing
• READMEs rewritten with live demo section, comparison table, platform examples, and matching header design
• Logo replaced with optimized webp
• Unit tests added

How Has This Been Tested?

• Unit tests covering crypto, payload encryption, request building, input validation, and CLI
• Live demo verified at pushforge.draphy.org on Cloudflare Workers

Checklist

• I have performed a self-review of my own code
• I have added tests to cover my changes

[linear]

WPN-29 Remove top level await in `crypto.ts`

[github-actions]

🎉 This PR is included in version 2.0.0 🎉

The release is available on GitHub release

Your semantic-release bot 📦🚀

[github-actions]

🎉 This PR is included in version 2.0.0 🎉

The release is available on GitHub release

Your semantic-release bot 📦🚀