feat(http): 为 http engine 添加直接处理响应体的能力，并优化 openai sse 处理逻辑

[sunist-c]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 2.02020% with 97 lines in your changes missing coverage. Please review.

Project coverage is 72.42%. Comparing base (5c68322) to head (6dc8d21).
Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
network/http/sse.go	0.00%	60 Missing ⚠️
network/http/endpoint.go	0.00%	25 Missing ⚠️
network/http/response.go	0.00%	6 Missing ⚠️
network/http/context.go	0.00%	4 Missing ⚠️
network/http/preprocessor.go	33.33%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #40      +/-   ##
==========================================
- Coverage   73.97%   72.42%   -1.56%     
==========================================
  Files          69       70       +1     
  Lines        4454     4551      +97     
==========================================
+ Hits         3295     3296       +1     
- Misses        926     1022      +96     
  Partials      233      233              

Files with missing lines	Coverage Δ
network/http/engine.go	71.18% <100.00%> (+0.49%)	⬆️
network/http/preprocessor.go	41.72% <33.33%> (-0.57%)	⬇️
network/http/context.go	97.96% <0.00%> (-2.04%)	⬇️
network/http/response.go	82.60% <0.00%> (-12.40%)	⬇️
network/http/endpoint.go	71.18% <0.00%> (-6.48%)	⬇️
network/http/sse.go	0.00% <0.00%> (ø)