Feat: support verify to set llm key and boost bigrams.

[KevinHuSh]

#12863

Type of change

• New Feature (non-breaking change which adds functionality)

[codecov]

Codecov Report

❌ Patch coverage is 18.29268% with 67 lines in your changes missing coverage. Please review.
✅ Project coverage is 44.13%. Comparing base (6f31c5f) to head (6901532).
⚠️ Report is 19 commits behind head on main.

Files with missing lines	Patch %	Lines
api/apps/canvas_app.py	18.03%	50 Missing ⚠️
api/apps/llm_app.py	19.04%	17 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #12980      +/-   ##
==========================================
- Coverage   44.46%   44.13%   -0.33%     
==========================================
  Files          43       43              
  Lines        9264     9378     +114     
  Branches      107      107              
==========================================
+ Hits         4119     4139      +20     
- Misses       5126     5220      +94     
  Partials       19       19              

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