fix(agent-tars): all existing llm setting issues

[ulivz]

• Closes: API key is required #257
• Closes: Model setup issues #259
• Closes: Cannot clean API Key setting #261
• Closes: Setting Store always got old value #270
• Closes: Clean endpoint does not take effect. #271
• Closes: Clean endpoint will cause unexpected issue #272
• Closes: Custom OpenAI base url does not work #274
• Related to: Agent TARS does not run well based on GPT-4o #273

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 9 lines in your changes missing coverage. Please review.

Project coverage is 4.61%. Comparing base (09500c0) to head (adab19c).

Files with missing lines	Patch %	Lines
.../components/LeftSidebar/Settings/useAppSettings.ts	0.00%	8 Missing ⚠️
apps/agent-tars/src/main/ipcRoutes/settings.ts	0.00%	1 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #276   +/-   ##
=====================================
  Coverage   4.61%   4.61%           
=====================================
  Files        257     256    -1     
  Lines       7913    7904    -9     
  Branches    1472    1472           
=====================================
  Hits         365     365           
+ Misses      7508    7499    -9     
  Partials      40      40           

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