fix: update Scaleway models list

[Quentinchampenois]

Description

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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 and include updated examples.

• 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 121c02f. Summary will update on new commits.}

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[Quentinchampenois]

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