feat: add new model provider AtlasCloud

[imdm]

What this PR does

Before this PR:

• Users could not access AtlasCloud AI models within Cherry Studio

After this PR:

• AtlasCloud is now integrated as a native model provider. Users can easily select AtlasCloud from the provider list, use its default API endpoint, and configure their API keys with a dedicated brand icon.

Fixes #

Why we need it and why it was done in this way

AtlasCloud (https://atlascloud.ai) provides high-performance LLM inference services. Adding it as a native provider enhances Cherry Studio's ecosystem and provides more choices for users in specific regions or those requiring specific model capabilities.

The following tradeoffs were made:

• Used OpenAI-compatible API format
• I followed the existing provider implementation pattern
• No major architectural changes were introduced

The following alternatives were considered:

• Leaving users to use the "Custom OpenAI" provider. However, a dedicated provider improves UX by providing pre-set endpoints and brand recognition.

Breaking changes

None. This PR only adds a new feature and does not affect existing providers or data structures.

Special notes for your reviewer

• Logo asset included and properly configured
• Verified the API compatibility with AtlasCloud's current documentation

Checklist

This checklist is not enforcing, but it's a reminder of items that could be relevant to every PR.
Approvers are expected to review this list.

• PR: The PR description is expressive enough and will help future contributors
• Code: Write code that humans can understand and Keep it simple
• Refactor: You have left the code cleaner than you found it (Boy Scout Rule)
• Upgrade: Impact of this change on upgrade flows was considered and addressed if required
• Documentation: A user-guide update was considered and is present (link) or not required. You want a user-guide update if it's a user facing feature.

Release note

Added AtlasCloud as a new model provider.

[YinsenWANG]

pending

[kangfenmao]

Thank you for taking the time to add AtlasCloud support.

Provider configuration and model registration have since moved to a new registry and generated provider-catalog workflow, while the files and integration paths used by this PR are no longer part of the current architecture. Because this implementation can no longer be merged safely as written, we're closing the PR.

AtlasCloud support itself is not being rejected. A fresh PR based on the current main branch and provider integration patterns would still be welcome, ideally including current endpoint details, supported models, and verification information.

Thank you again for the contribution.