chore: retrain edge classifier, upgrade PrivacyGatekeeper to v2.1.0, and clean up unused Model2Vec assets

[StoyanD]

Summary

This PR merges version bumps and updates related to retraining the edge classifier, transitioning to `NLContextualEmbedding` by default, upgrading the `PrivacyGatekeeper` model, and cleaning up unused

legacy assets.

### Details of Changes
* **Classifier & Embedding Upgrades**:
  * Retrained the edge classifier and optimized layout noise filters to improve accuracy.
  * Deployed `NLContextualEmbedding` as the default model (v2.0.0).
  * Updated the `PrivacyGatekeeper` model and bumped version to v2.1.0.
* **Cleanup**:
  * Removed the unused `Model2Vec` classifier, dependencies, and obsolete assets.
* **Tooling & Scripts**:
  * Configured Antigravity git tooling and updated `Package.swift` dependencies.
  * Added the `push_sanitized_extractions` utility script.