feat: add TwelveLabs Marengo embeddings and Pegasus video loader

[mohit-twelvelabs]

Hi! I'm Mohit, I work at TwelveLabs (@mohit-twelvelabs).

Description

This PR adds a new opt-in package, @llm-tools/embedjs-twelvelabs, that brings TwelveLabs video understanding to embedJs:

• MarengoEmbeddings — a drop-in embedding model backed by the Marengo (marengo3.0) multimodal model. Marengo embeds text, image, audio and video into a single shared 512-dimensional latent space, which is a strong fit for RAG over video and mixed-media libraries.
• TwelveLabsVideoLoader — a data source that analyses a video with the Pegasus video understanding model (it watches the visuals, motion and audio) and loads the resulting natural-language description into the RAG pipeline. This lets you index video content directly from a public URL, with no separate transcription step.

It mirrors the existing provider conventions (e.g. embedjs-openai, embedjs-cohere, embedjs-loader-youtube): same package scaffolding, Nx project.json, tsconfig/eslint config, BaseEmbeddings / BaseLoader extension, and docs.

Why it helps this project: it's the first multimodal/video-native option in embedJs — users can now build RAG apps over video without leaving the framework. It's fully opt-in and non-breaking — a new workspace package with its own dependency; no existing defaults or behaviour change.

Fixes # (no issue)

Type of change

• New feature (non-breaking change which adds functionality)
• Documentation update

How Has This Been Tested?

Built the package with Nx (nx build embedjs-twelvelabs) and exercised it against the live TwelveLabs API with a real key:

• MarengoEmbeddings.getDimensions() returns 512; embedQuery and embedDocuments return real 512-dim vectors.
• TwelveLabsVideoLoader construction, uniqueId and the chunk generator wiring verified; full Pegasus analysis of a public URL works server-side but is slow, so the request wiring is verified and a full run is left to the reviewer.
• Both classes throw a clear error when no API key is supplied (via constructor or TWELVELABS_API_KEY).

You can grab a free API key at https://twelvelabs.io — there's a generous free tier.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new tsc or eslint warnings
• I have checked my code and corrected any misspellings

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud