feat: improve the error handling of assistant API

[wangl-cc]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 33.33333% with 10 lines in your changes missing coverage. Please review.

Project coverage is 66.07%. Comparing base (65bbb8c) to head (c4da95c).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
maa-sys/src/lib.rs	33.33%	10 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #346      +/-   ##
==========================================
+ Coverage   65.94%   66.07%   +0.12%     
==========================================
  Files          42       42              
  Lines        3627     3626       -1     
==========================================
+ Hits         2392     2396       +4     
+ Misses       1235     1230       -5     

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