docs: update README

[embano1]

Issue #, if available: n/a

Description of changes:

PR Summary: Enhance Root README for Better Developer Onboarding

Status Badges Added

• Build – GitHub Actions workflow status
• NPM Version – Current SDK version on npm
• OpenSSF Scorecard – Security scorecard (existing)
• License – Apache 2.0 license badge
• Node.js – Minimum version requirement (≥22)
• TypeScript – TypeScript 5.x support

New Sections

1. Hero Section – Compelling one-liner explaining the value proposition
2. ✨ Key Features – 7 bullet points highlighting core capabilities
3. 📦 Packages Table – Lists all 3 NPM packages with descriptions and individual npm version badges
4. 🚀 Quick Start – Installation + complete code example demonstrating:
   • Root context logger (context.logger.info)
   • Step-scoped logger (stepCtx.logger.debug)
   • Steps and wait operations
5. 📚 Documentation – Links to AWS docs, SDK README, API reference, concepts, and examples
6. 🧪 Testing – Testing SDK usage showing:
   • skipTime: true for fast-forwarding through waits
   • Assertions for execution status, result, invocations count, and operations count
   • Operation inspection by name
7. 💬 Feedback & Support – Direct links to issue templates:
   • Bug reports
   • Feature requests
   • Documentation issues
   • GitHub Discussions

Benefits

• Developers can understand the SDK's purpose within seconds
• Project health visible at a glance via badges
• Copy-paste ready code example to get started quickly
• Clear paths to documentation and support channels

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[embano1]

@anthonyting done