ci(vocs): hard copy all symlink dirs

[jonathanpwang]

deployed: https://github.com/openvm-org/openvm/actions/runs/17385905364

[Copilot]

Pull Request Overview

Updates the build process to use a more maintainable approach for handling symlinked directories during Vercel deployment. The change replaces repetitive copy commands with a loop-based solution.

• Simplifies the vercel-build script by using a for loop instead of repeated commands
• Adds a new symlinked directory examples_sdk_guest to the build process
• Updates the package name from "OpenVM Docs" to "@openvm/docs" for consistency

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