Add CrewAI instrumentation: LLM inference event listener

[venkata-pavani]

Ports the LLM-call slice of the donated OpenInference CrewAI instrumentation onto opentelemetry-util-genai: an event-bus listener converts LLMCallStarted/Completed/Failed events into chat inference invocations (usage tokens, response id, finish reasons, content capture).

Tests: unit tests driving the listener with real CrewAI events, a VCR-backed Agent.kickoff() integration test, and a weaver conformance scenario - both replaying the genuinely-recorded inference cassette ported unchanged from
open-telemetry/donation-openinference (commit 6cdd644d).

The conformance tox env overrides crewai's opentelemetry-api pins via UV_OVERRIDE (tests/overrides-conformance.txt) so it can resolve against the git-pinned conformance stack.

Known gap: CrewAI's event bus dispatches handlers on a thread pool, so util-genai's context attach/detach logs a ValueError per LLM call; fix requires an attach_context opt-out in util-genai (separate discussion).

Assisted-by: Claude Fable 5

Description

Please include a summary of the change and which issue, if any, is fixed.
Include the motivation and context for the change.

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• 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?

Please describe the tests that you ran to verify your changes. Provide
instructions so we can reproduce. List any relevant details for your test
configuration.

• Test A

Checklist

See CONTRIBUTING.md
for the style guide, changelog guidance, and more.

• Followed the style guidelines of this project
• Changelog updated if the change requires an entry
• Unit tests added
• Documentation updated

[linux-foundation-easycla]

• ❌ The email address for the commit (1cd470a) is not linked to the GitHub account, preventing the EasyCLA check. Consult this Help Article and GitHub Help to resolve. (To view the commit's email address, add .patch at the end of this PR page's URL.) For further assistance with EasyCLA, please visit our EasyCLA portal and chat with our support bot.
• ❌ - login: @venkata-pavani / name: Pavani N. The commit (1cd470a) is not authorized under a signed CLA. Please click here to be authorized. For further assistance with EasyCLA, please visit our EasyCLA portal and chat with our support bot.

One or more co-authors of this pull request were not found. You must specify co-authors in commit message trailer via:

Co-authored-by: name <email>

Supported Co-authored-by: formats include:

1. Anything <id+login@users.noreply.github.com> - it will locate your GitHub user by id part.
2. Anything <login@users.noreply.github.com> - it will locate your GitHub user by login part.
3. Anything <public-email> - it will locate your GitHub user by public-email part. Note that this email must be made public on Github.
4. Anything <other-email> - it will locate your GitHub user by other-email part but only if that email was used before for any other CLA as a main commit author.
5. login <any-valid-email> - it will locate your GitHub user by login part, note that login part must be at least 3 characters long.

Alternatively, if the co-author should not be included, remove the Co-authored-by: line from the commit message.

Please update your commit message(s) by doing git commit --amend and then git push [--force] and then request re-running CLA check via commenting on this pull request:

/easycla