feat: add Atlas Cloud as an OpenAI-compatible LLM provider

[lucaszhu-hue]

Description

This PR adds Atlas Cloud as a new LLM provider. Atlas Cloud is an OpenAI-compatible API gateway that provides access to 300+ open-source and frontier models (DeepSeek, Llama, Qwen, and more).

Implementation mirrors the existing OpenAI-compatible providers (e.g. Tensorix, Deepseek): AtlasCloud extends the OpenAI base class and only overrides apiBase (https://api.atlascloud.ai/v1/) and the default model (deepseek-ai/deepseek-v4-pro). The API key is supplied via the standard apiKey config field.

Changes

• core/llm/llms/AtlasCloud.ts — new provider class extending OpenAI
• core/llm/llms/index.ts — register the provider
• core/llm/autodetect.ts — add to templating/parallel provider lists
• packages/openai-adapters/src/index.ts + types.ts — OpenAI-compatible adapter mapping
• gui/src/pages/AddNewModel/configs/providers.ts — Add Model UI entry
• extensions/vscode/config_schema.json — config schema enum + description
• docs/docs.json + docs/customize/model-providers/more/atlascloud.mdx — provider docs

Notes

• Atlas Cloud is fully OpenAI-compatible; the API key is read from the standard apiKey field.
• For questions or partnership, contact marketing@atlascloud.ai.

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Summary by cubic

Adds Atlas Cloud as an OpenAI‑compatible LLM provider. You can now choose atlascloud to use 300+ models via https://api.atlascloud.ai/v1/ (default: DeepSeek V4 Pro).

• New Features
  • New AtlasCloud class extends OpenAI and defines api base and default model.
  • Provider registered in core, including templating, image support, and parallel lists.
  • packages/openai-adapters maps atlascloud to the OpenAI-compatible adapter.
  • VS Code schema and Add Model UI updated; uses apiKey.
  • Docs added with setup examples and nav entry.

^{Written for commit 50918a3. Summary will update on new commits.}

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[cubic-dev-ai]

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