feat(crewai): add GenAI util instrumentation

[sipercai]

Description

This PR updates the LoongSuite CrewAI instrumentation to build GenAI telemetry through opentelemetry-util-genai, including Crew/Flow entry spans, agent/task/tool spans, token usage, streaming behavior, and safe instrumentation failure handling. It also adds a real CrewAI smoke example for sync, streaming, and concurrent runs, and refreshes the README and changelog.

Fixes # (N/A)

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

• uvx tox -e precommit
• uvx tox -c tox-loongsuite.ini -e lint-loongsuite-instrumentation-crewai
• uvx tox -c tox-loongsuite.ini -e py312-test-loongsuite-instrumentation-crewai

Does This PR Require a Core Repo Change?

• Yes. - Link to PR:
• No.

Checklist:

See contributing.md for styleguide, changelog guidelines, and more.

• Followed the style guidelines of this project
• Changelogs have been updated
• Unit tests have been added
• Documentation has been updated

[sipercai]

Migrated to an upstream repository branch PR for Copilot review and organization-side review flow: #198