chore: add pre-push hook for cargo fmt and clippy

[Lewis-E]

Summary

• Adds .githooks/pre-push with cargo fmt --check and cargo clippy -D warnings
• Hook is committed to the repo and includes output with a fix for LLMs
• Also fixes two pre-existing clippy/fmt issues caught by the hook

Setup

Each contributor needs to run once:

git config core.hooksPath .githooks

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR adds a repository-managed Git pre-push hook to enforce Rust formatting and clippy checks before code is pushed, and includes a couple of small test cleanups driven by fmt/clippy.

Changes:

• Add .githooks/pre-push to run cargo fmt --check and cargo clippy prior to pushing.
• Simplify assertions in dogstatsd origin tests to satisfy clippy/fmt.
• Refactor readiness polling in a trace-agent integration test using a let-chain condition.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
crates/dogstatsd/src/origin.rs	Minor assertion cleanup in tests (clippy/fmt-driven).
crates/datadog-trace-agent/tests/integration_test.rs	Simplifies server readiness polling logic in an integration test.
.githooks/pre-push	Introduces a pre-push hook to run cargo fmt and cargo clippy locally before pushing.

[Lewis-E]

/merge

[gh-worker-devflow-routing-ef8351]

View all feedbacks in Devflow UI.

2026-05-07 15:06:12 UTC ℹ️ Start processing command /merge

---

2026-05-07 15:06:19 UTC ℹ️ MergeQueue: waiting for PR to be ready

This pull request is not mergeable according to GitHub. Common reasons include pending required checks, missing approvals, or merge conflicts — but it could also be blocked by other repository rules or settings.
It will be added to the queue as soon as checks pass and/or get approvals. View in MergeQueue UI.
Note: if you pushed new commits since the last approval, you may need additional approval.
You can remove it from the waiting list with /remove command.

---

2026-05-07 15:07:10 UTC ℹ️ MergeQueue: merge request added to the queue

The expected merge time in main is approximately 0s (p90).

---

2026-05-07 15:08:00 UTC ❌ MergeQueue: This merge request was updated

This PR is rejected because it was updated

[Lewis-E]

Think this needs #129 to stop failing unrelated tests