Add e2e tests for embedding raw flag

[SamMalayek]

🧩 Summary

This PR adds a CI workflow for end-to-end embedding CLI tests (none exist today). It establishes a small, fast, reproducible baseline for validating embedding behavior (dimensions + determinism) using tiny GGUF models.

Discussion / design context: See the companion RFC in Discussions for the longer-term plan to add a native server endpoint: #16957

⚙️ What this PR includes

• A GitHub Actions job (embeddings.yml) that runs E2E embedding CLI tests with cached tiny models (e.g., TinyLlama).
• Checks output dimensions and deterministic behavior.
• Keeps runs lightweight and fast; an optional large-model stress test can be added later.

[CISC]

While testing is great I have issues with this PR:

• The CI only runs when the example code change, not when actual embedding code changes
• The tests are not testing anything likely to break, nor indeed even anything useful

To sum up; overall as a CI job this will not run when it matters, and when it is run it will not catch any problems of consequence.

Lastly, why create a new PR instead of arguing your case in the original PR and maybe iron out concerns there?

[SamMalayek]

While testing is great I have issues with this PR:

• The CI only runs when the example code change, not when actual embedding code changes
• The tests are not testing anything likely to break, nor indeed even anything useful

To sum up; overall as a CI job this will not run when it matters, and when it is run it will not catch any problems of consequence.

I kept them in examples alongside the CLI code as a pragmatic, incremental, small first step. The intent was to expand scope and relocate to tests/e2e/embedding/ once the embedding path itself was integrated into the server runtime (or simply commonized as an intermediary step). That said, I can move them now and broaden coverage to better match expectations (done).

Lastly, why create a new PR instead of arguing your case in the original PR and maybe iron out concerns there?

That PR was closed with minimal comment. There appeared to be no room for discussion.

[SamMalayek]

Note: Empty force-pushes are to re-trigger the CI workflow following an intermittent failure.

[SamMalayek]

Putting this in draft while work on the RFC continues.