feat(telemetry): updated semantic conventions, added timeToFirstByteMs into spans and metrics

[poshinchen]

Description

• Added timeToFirstByteMs into the spans and metrics
• Updated semantic conventions for tool requests and response
  • Mapped the contentBlock, toolUse and ToolResponse to the expected OTEL conventions (input schema, output schema)

Related Issues

#986

Documentation PR

N/A

Type of Change

New feature

Testing

How have you tested the change? Verify that the changes do not break functionality or introduce warnings in consuming repositories: agents-docs, agents-tools, agents-cli

• I ran hatch run prepare

Checklist

• I have read the CONTRIBUTING document
• I have added any necessary tests that prove my fix is effective or my feature works
• I have updated the documentation accordingly
• I have added an appropriate example to the documentation to outline the feature, or no new docs are needed
• My changes generate no new warnings
• Any dependent changes have been merged and published

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[codecov]

Codecov Report

❌ Patch coverage is 84.31373% with 8 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/strands/telemetry/tracer.py	82.75%	3 Missing and 2 partials ⚠️
src/strands/event_loop/streaming.py	84.61%	1 Missing and 1 partial ⚠️
src/strands/telemetry/metrics.py	75.00%	0 Missing and 1 partial ⚠️

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