Error during code context and indexing

[magesh-presidio]

Description

• The encoding logic for "gpt-4o" was causing failures, resulting in code context error and workspace restoration alerts.
• Token calculation operations were blocking the main thread, preventing extension UI from loading properly.

Type of Change

• 🐛 Bug fix (non-breaking change which fixes an issue)
• ✨ New feature (non-breaking change which adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📚 Documentation update

Pre-flight Checklist

• Changes are limited to a single feature, bugfix or chore (split larger changes into separate PRs)
• Tests are passing (npm test) and code is formatted and linted (npm run format && npm run lint)
• I have reviewed contributor guidelines