fix: grace shutdown for gw

[rfyiamcool]

summary

add grace shutdonw for gateway server.

[sweep-ai]

Apply Sweep Rules to your PR?

• Apply: All new business logic should have corresponding unit tests.
• Apply: Refactor large functions to be more modular.
• Apply: Add docstrings to all functions and file headers.

[codecov]

Codecov Report

Attention: 74 lines in your changes are missing coverage. Please review.

Comparison is base (f935d36) 4.97% compared to head (8d0d7ae) 4.90%.

Files	Patch %	Lines
internal/msggateway/n_ws_server.go	0.00%	33 Missing ⚠️
pkg/common/startrpc/start.go	0.00%	30 Missing ⚠️
internal/msggateway/init.go	0.00%	11 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##            main   #1478      +/-   ##
========================================
- Coverage   4.97%   4.90%   -0.08%     
========================================
  Files         49      49              
  Lines       4162    4224      +62     
========================================
  Hits         207     207              
- Misses      3943    4005      +62     
  Partials      12      12              

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