Add Cerebras API + node validation for airetry!

[svilupp]

Added

• Added support for Cerebras hosted models (set your ENV CEREBRAS_API_KEY). Available model aliases: cl3 (Llama3.1 8bn), cl70 (Llama3.1 70bn).
• Added a kwarg to aiclassify to provide a custom token ID mapping (token_ids_map) to work with custom tokenizers.

Updated

• Improved the implementation of airetry! to concatenate feedback from all ancestor nodes ONLY IF feedback_inplace=true (because otherwise LLM can see it in the message history).

Fixed

• Fixed a potential bug in airetry! where the aicall object was not properly validated to ensure it has been run! first.

[svilupp]

Closes #216

[codecov]

Codecov Report

Attention: Patch coverage is 78.94737% with 4 lines in your changes missing coverage. Please review.

Project coverage is 91.47%. Comparing base (188ede9) to head (7c1722c).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/llm_openai.jl	66.66%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #217      +/-   ##
==========================================
- Coverage   91.54%   91.47%   -0.07%     
==========================================
  Files          46       46              
  Lines        4425     4436      +11     
==========================================
+ Hits         4051     4058       +7     
- Misses        374      378       +4     

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[svilupp]

CI failure looks related to Documenter.jl. Unrelated to the current PR! Will proceed