docs: add DaoXE as OpenAI-compatible cloud-proxy example

[seven7763]

Description

Adds a minimal example for DaoXE under Other OpenAI-compatible providers in the cloud passthrough proxy docs.

DaoXE is an OpenAI-compatible multi-model API gateway (https://daoxe.com/v1). This shows how to configure LocalAI's cloud-proxy backend to forward chat completions to it, with a note that model IDs are account-scoped.

Changes

• docs/content/features/cloud-proxy.md — short DaoXE example YAML next to Together/Groq-style providers

Checklist

• Docs only; no code/runtime changes
• Follows existing cloud-proxy example style
• English

[localai-bot]

Thanks for the example. A few things before this can be considered:

1. DCO check is failing. Please sign off your commit: git commit --amend -s and push again to your branch.
2. Style nit: please replace the em dash in the added paragraph with a plain sentence break or parentheses, matching the surrounding docs.
3. The snippet itself is consistent with the passthrough examples above it (provider, upstream_url, api_key_env, upstream_model all look right).

Leaving the final call on listing this specific commercial gateway in the docs to @mudler.