fix: update Scaleway models list

[Quentinchampenois]

Description

[ What changed? Feel free to be brief. ]

AI Code Review

• Team members only: AI review runs automatically when PR is opened or marked ready for review
• Team members can also trigger a review by commenting @continue-review

Checklist

• I've read the contributing guide
• The relevant docs, if any, have been updated or created
• The relevant tests, if any, have been updated or created

Screen recording or screenshot

[ When applicable, please include a short screen recording or screenshot - this makes it much easier for us as contributors to review and understand your changes. See this PR as a good example. ]

Tests

[ What tests were added or updated to ensure the changes work as expected? ]

---

Summary by cubic

Updated Scaleway model mappings to match the latest catalog and set qwen3.6-35b-a3b as the default. Docs now recommend qwen3.6-35b-a3b with updated examples and page copy.

• Bug Fixes
  • Default model: qwen3.6-35b-a3b
  • Added: mistral-medium3.5, devstral-2, qwen3.6-35b-a3b, gemma-4-26b-a4b, qwen3.5-397b-a17b, bge-multilingual-gemma2, qwen3-embedding-8b
  • Removed: llama3.1-8b, mistral-small3.1, devstral-small, deepseek-r1-distill-llama-70b, qwen2.5-coder-32b

^{Written for commit 7ce6e6d. Summary will update on new commits.}

[github-actions]

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

[Quentinchampenois]

I have read the CLA Document and I hereby sign the CLA

[cubic-dev-ai]

No issues found across 2 files

_{Re-trigger cubic}