chore: add pre-commit config for local Rust lint checks (#1871)

# What does this PR do?

Adds a `.pre-commit-config.yaml` that mirrors CI lint checks for local
development:
- **pre-commit**: `cargo +nightly-2026-02-08 fmt --all` and
`dd-rust-license-tool check` (only on Cargo.toml/lock and license input
changes)
- **pre-push**: `cargo clippy --workspace --all-targets --all-features
-- -D warnings`

# Motivation

Since I started using coding agents, I find pre-commit hooks invaluable
— they greatly reduce back-and-forths and CI costs. The more checks that
run locally before code leaves my machine, the fewer wasted CI cycles
and review round-trips.

I'm not specifically promoting [pre-commit](https://pre-commit.com/)
(the Python tool), but it's a nice framework that's trivial to install,
especially with `uv`:

```bash
uv tool install pre-commit
```

There are probably a million similar frameworks, but this is a nice
example.

# Additional Notes

Completely opt-in. If you haven't configured the git hooks locally, none
of these checks will fire. Install with:

```bash
GIT_CONFIG_GLOBAL=/dev/null pre-commit install
GIT_CONFIG_GLOBAL=/dev/null pre-commit install --hook-type pre-push
```

(`GIT_CONFIG_GLOBAL=/dev/null` works around the DD global
`core.hooksPath` setting.)

rustfmt is pinned to `nightly-2026-02-08` to match CI. Common Components
will follow up with a `rust-toolchain.toml` to make this easier to keep
in sync.

# How to test the change?

1. Install hooks as above
2. Modify a `.rs` file and commit — `cargo fmt` runs automatically
3. Push — `cargo clippy` runs before the push goes through
4. Modify a `Cargo.toml` and commit — `dd-rust-license-tool check` runs

Author: pawelchcki

.github/CODEOWNERS

@@ -4,6 +4,7 @@
 
 .claude/                             @DataDog/apm-common-components-core
 .clang-format                        @DataDog/libdatadog
+.pre-commit-config.yaml              @DataDog/libdatadog-core
 .codecov.yml                         @DataDog/apm-common-components-core
 .cargo/*                             @DataDog/libdatadog-core
 .config/nextest.toml                 @DataDog/apm-common-components-core

.pre-commit-config.yaml

@@ -0,0 +1,36 @@
+# Pre-commit configuration for libdatadog
+#
+# Install (GIT_CONFIG_GLOBAL=/dev/null works around DD core.hooksPath):
+#   GIT_CONFIG_GLOBAL=/dev/null pre-commit install
+#   GIT_CONFIG_GLOBAL=/dev/null pre-commit install --hook-type pre-push
+#
+# Mirrors CI checks from .github/workflows/lint.yml:
+#   pre-commit: cargo +nightly-2026-02-08 fmt --all
+#   pre-push:   cargo clippy --workspace --all-targets --all-features -- -D warnings
+#   pre-commit: dd-rust-license-tool check (on dependency/license file changes)
+repos:
+  - repo: local
+    hooks:
+      - id: cargo-fmt
+        name: cargo fmt
+        language: system
+        # Pinned to match CI (.github/workflows/lint.yml). Keep this in sync.
+        entry: cargo +nightly-2026-02-08 fmt --all --
+        types: [rust]
+        pass_filenames: false
+
+      - id: cargo-clippy
+        name: cargo clippy
+        language: system
+        entry: cargo clippy --workspace --all-targets --all-features -- -D warnings
+        types: [rust]
+        pass_filenames: false
+        stages: [pre-push]
+
+      - id: license-3rdparty
+        name: dd-rust-license-tool check
+        language: system
+        # CI pins version 1.0.6 — install with: cargo install dd-rust-license-tool --version 1.0.6
+        entry: dd-rust-license-tool check
+        files: (Cargo\.toml|Cargo\.lock|license-tool\.toml|LICENSE-3rdparty\.csv)$
+        pass_filenames: false

CONTRIBUTING.md

@@ -91,6 +91,9 @@ If you'd like CI to automatically format your code and commit the changes to you
 label to your pull request. This will trigger a one-time formatting commit if any changes are needed. If you push
 additional commits after labeling, remove and re-add the label to re-run formatting.
 
+Optionally, you can install [pre-commit](https://pre-commit.com/) hooks to run formatting and clippy checks locally
+before they hit CI. See `.pre-commit-config.yaml` for setup instructions.
+
 ## Commit Message Guidelines
 
 This project uses [Conventional Commits](https://www.conventionalcommits.org/) for commit messages and pull request titles.