feat: add mocks and unit test for router.ts

[SuZhou-Joe]

Description

1. Add unit test for routes.ts
2. Add mocks for StorageService and ChatService.
3. Optimize error handling in send_message router.

Issues Resolved

List any issues this PR will resolve, e.g. Closes [...].

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (36ac34b) 23.28% compared to head (55e831c) 36.61%.
Report is 4 commits behind head on feature/agent-framework.

Additional details and impacted files

@@                     Coverage Diff                      @@
##           feature/agent-framework      #57       +/-   ##
============================================================
+ Coverage                    23.28%   36.61%   +13.32%     
============================================================
  Files                           42       46        +4     
  Lines                          919     1087      +168     
  Branches                       227      250       +23     
============================================================
+ Hits                           214      398      +184     
+ Misses                         698      681       -17     
- Partials                         7        8        +1     

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