feat: 支持通过opentelemetry上报metrics

[weimch]

• 也支持custom_metrics方便在解析远程Agent响应到框架上报指标中使用

[github-actions]

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[weimch]

I have read the CLA Document and I hereby sign the CLA

[codecov]

Codecov Report

❌ Patch coverage is 92.59259% with 18 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (main@d81f519). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
trpc_agent_sdk/agents/_base_agent.py	71.42857%	8 Missing ⚠️
trpc_agent_sdk/agents/core/_llm_processor.py	86.66667%	4 Missing ⚠️
trpc_agent_sdk/telemetry/_custom_metrics.py	95.89041%	3 Missing ⚠️
trpc_agent_sdk/server/a2a/_remote_a2a_agent.py	33.33333%	2 Missing ⚠️
trpc_agent_sdk/agents/core/_tools_processor.py	80.00000%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main         #48   +/-   ##
==========================================
  Coverage        ?   86.94249%           
==========================================
  Files           ?         382           
  Lines           ?       35336           
  Branches        ?           0           
==========================================
  Hits            ?       30722           
  Misses          ?        4614           
  Partials        ?           0           

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[weimch]

I have read the CLA Document and I hereby sign the CLA