feat: add wall-clock time display in timeline

[lukecotter]

📝 PR Overview

Adds a wall-clock time display toggle to the timeline, allowing users to switch between elapsed time and real-time (HH:MM:SS.mmm) on the time axis. Also condenses the Timeline feature list in the README for better scannability.

🛠️ Changes made

• Implement wall-clock time display toggle in the timeline toolbar (clock button)
• Parse and surface wall-clock timestamps from log events
• Add wall-clock formatting utility with HH:MM:SS.mmm display
• Update time axis rendering to support both elapsed and wall-clock modes
• Update tooltips to show wall-clock time when enabled
• Update codicons to v0.0.44 for new icons
• Condense README timeline section from 14 bullets to 5 hero highlights + compact "Also" line
• Update CHANGELOG with wall-clock time toggle feature

🧩 Type of change (check all applicable)

• 🐛 Bug fix - something not working as expected
• ✨ New feature – adds new functionality
• ♻️ Refactor - internal changes with no user impact
• ⚡ Performance Improvement
• 📝 Documentation - README or documentation site changes
• 🔧 Chore - dev tooling, CI, config
• 💥 Breaking change

🔗 Related Issues

resolves #685
related #446

✅ Tests added?

• 👍 yes
• 🙅 no, not needed
• 🙋 no, I need help

📚 Docs updated?

• 🔖 README.md
• 🔖 CHANGELOG.md
• 📖 help site
• 🙅 not needed