fix: bundle dependencies for GitHub Action execution

[dcramer]

Summary

• Switched from TypeScript compilation to tsdown bundling to fix GitHub Action execution
• All dependencies are now bundled into a single minified dist/index.js file
• This resolves the issue where the v0 tag wasn't working correctly in production

Problem

The GitHub Action was failing in production because it was trying to import dependencies that weren't available at runtime. GitHub Actions require all dependencies to be bundled into the distribution files.

Solution

• Added tsdown as a bundler
• Updated build scripts to use tsdown instead of tsc
• Bundled all dependencies into a single minified file
• Removed unnecessary build artifacts

Test plan

• Run pnpm run validate - all tests pass
• Verify dist/index.js contains bundled dependencies
• Test the action on a pull request after merging