✨ feat: add Mistral model support in Bedrock

[hezhijie0327]

💻 变更类型 | Change Type

• ✨ feat
• 🐛 fix
• ♻️ refactor
• 💄 style
• 👷 build
• ⚡️ perf
• 📝 docs
• 🔨 chore

🔀 变更说明 | Description of Change

1. 增加对 Bedrock 中 Mistral (mistral.mistral-small-2402-v1:0, mistral.mistral-large-2402-v1:0, mistral.mistral-large-2407-v1:0) 模型的对话支持
2. TODO: 待已支持 tools_call

Note: mistral.mistral-large-2407-v1:0 仅在 us-west-2 可用

📝 补充信息 | Additional Information

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[codecov]

Codecov Report

Attention: Patch coverage is 61.87500% with 61 lines in your changes missing coverage. Please review.

Project coverage is 91.67%. Comparing base (743df51) to head (df25599).
Report is 31 commits behind head on main.

Files with missing lines	Patch %	Lines
src/libs/agent-runtime/bedrock/index.ts	9.25%	49 Missing ⚠️
...ibs/agent-runtime/utils/streams/bedrock/mistral.ts	88.46%	12 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3810      +/-   ##
==========================================
- Coverage   91.78%   91.67%   -0.12%     
==========================================
  Files         453      456       +3     
  Lines       30201    30592     +391     
  Branches     2084     2124      +40     
==========================================
+ Hits        27719    28044     +325     
- Misses       2482     2548      +66     

Flag	Coverage Δ
app	91.67% <61.87%> (-0.12%)	⬇️
server	97.36% <ø> (ø)

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[arvinxx]

stream 的部分需要补单测，不加的话基本上过段时间就看不懂了。

参考 https://github.com/hezhijie0327/lobe-chat/blob/bedrock_mistral/src/libs/agent-runtime/utils/streams/openai.test.ts ，加一个基础的 text 和一个 tools 的

[hezhijie0327]

加上了