docs: docs(contributing): add newcomer contribution path and community expe...

CONTRIBUTING.md

@@ -7,6 +7,33 @@
 
 Thank you for your interest in contributing to NVIDIA NemoClaw. This guide covers how to set up your development environment, run tests, and submit changes.
 
+All participants are expected to follow our [Code of Conduct](CODE_OF_CONDUCT.md).
+
+## Types of Contributions
+
+We welcome many types of contributions:
+
+| Contribution type | Description |
+|---|---|
+| **Bug reports** | Confirmed bugs with reproduction steps — see [Before You Open an Issue](#before-you-open-an-issue) |
+| **Documentation fixes** | Typos, clarifications, and missing information in `docs/` |
+| **Tests** | New or improved test coverage in `test/` or `nemoclaw/test/` |
+| **Feature proposals** | Design-first proposals opened as issues before any implementation |
+| **Integrations** | Support for new inference backends, providers, or tools |
+| **Examples** | Worked usage examples added under `docs/` |
+
+Security vulnerabilities must follow [SECURITY.md](SECURITY.md) — **not** GitHub issues.
+
+## Where to Start
+
+New contributors should start with issues labeled [`good first issue`](https://github.com/NVIDIA/NemoClaw/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+first+issue%22). These are scoped tasks with clear acceptance criteria that do not require deep project knowledge.
+
+Before starting larger work:
+
+- Search open issues and pull requests to avoid duplicates.
+- Open an issue to discuss your approach before writing code for significant changes.
+- For questions, open a [GitHub Discussion](https://github.com/NVIDIA/NemoClaw/discussions) or comment on a related issue.
+
 ## Before You Open an Issue
 
 Open an issue when you encounter one of the following situations.
@@ -166,7 +193,19 @@ For user-skill definitions, docs-to-skills validation, release-prep regeneration
 
 ## Pull Requests
 
-We welcome contributions. Every PR requires maintainer review. To keep the review queue healthy, limit the number of open PRs you have at any time to fewer than 10.
+We welcome contributions. Every PR requires maintainer review before merge. To keep the review queue healthy, limit the number of open PRs you have at any time to fewer than 10.
+
+Maintainers review all incoming PRs on a best-effort basis. Straightforward fixes typically receive initial feedback sooner than large or complex changes. If a PR has not received a response after two weeks, a polite comment asking for an update is welcome.
+
+### DCO Sign-Off
+
+This project requires a [Developer Certificate of Origin (DCO)](https://developercertificate.org/) sign-off on every commit. Add the following trailer to each commit message:
+
+```text
+Signed-off-by: Your Name <your.email@example.com>
+```
+
+Use `git commit -s` to add the sign-off automatically. CI will reject commits that are missing it.
 
 > [!WARNING]
 > Accounts that repeatedly exceed this limit or submit automated bulk PRs may have their PRs closed or their access restricted.

test/e2e-scenario/framework-tests/e2e-lib-helpers.test.ts

@@ -751,13 +751,16 @@ describe("Phase 1.C fixtures", () => {
   });
 
   it("older_base_image_should_emit_dockerfile_pointing_at_tagged_base", () => {
-    const r = runBash(`
+    const r = runBash(
+      `
       set -euo pipefail
       . "${FIXTURES}/older-base-image.sh"
       df="$(older_base_image_prepare v0.0.1-test)"
       echo "DF=$df"
       head -n1 "$df"
-    `);
+    `,
+      { E2E_DRY_RUN: "1" },
+    );
     expect(r.status, r.stderr).toBe(0);
     expect(r.stdout).toMatch(/^FROM .*:v0\.0\.1-test/m);
   });