(feat) VoyageAI integration improvements

[fzowl]

Supporting VoyageAI's contextual model
Counting tokens and creating efficient batches
Documentation change: Unstructured-IO/docs#790

[fzowl]

@MthwRobinson, can you please help me resolve the issue? Also, please check the code.

[fzowl]

Hi @MthwRobinson 👋

The CI failure is not related to the code changes. The check-version job is failing with:
"Need to provide at least one botToken or webhookUrl"

This is a Slack notification configuration issue in the Release Version Alert workflow. All the actual code checks (tests, linting, type checking, etc.) are passing ✅
Could you either:

• Re-run the workflow with the proper credentials, or
• Skip this check for this PR?

Thanks!

[cragwolfe]

thank you @fzowl !