feat: add retro achievements link (#36)

### Explanation

_No response_

### Issue

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### Attestations

- [x] I have read and agree to the [Code of Conduct](https://docs.nhcarrigan.com/community/coc/)
- [x] I have read and agree to the [Community Guidelines](https://docs.nhcarrigan.com/community/guide/).
- [x] My contribution complies with the [Contributor Covenant](https://docs.nhcarrigan.com/dev/covenant/).

### Dependencies

- [ ] I have pinned the dependencies to a specific patch version.

### Style

- [x] I have run the linter and resolved any errors.
- [x] My pull request uses an appropriate title, matching the conventional commit standards.
- [x] My scope of feat/fix/chore/etc. correctly matches the nature of changes in my pull request.

### Tests

- [x] My contribution adds new code, and I have added tests to cover it.
- [ ] My contribution modifies existing code, and I have updated the tests to reflect these changes.
- [x] All new and existing tests pass locally with my changes.
- [x] Code coverage remains at or above the configured threshold.

### Documentation

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### Versioning

Patch - My pull request introduces bug fixes ONLY.

Reviewed-on: https://codeberg.org/nhcarrigan/portfolio/pulls/36
Co-authored-by: Naomi Carrigan <commits@nhcarrigan.com>
Co-committed-by: Naomi Carrigan <commits@nhcarrigan.com>

test/config/Socials.spec.ts

@@ -37,6 +37,14 @@ describe("socials objects", () => {
     );
     expect(set, "are not unique").toHaveLength(Socials.length);
   });
+
+  it("should have hex codes for colours", () => {
+    expect.hasAssertions();
+    for (const social of Socials) {
+      expect(social.color, `${social.label} is not a hex code`).toMatch(/^#[\da-f]{6}$/i);
+      expect(social.background, `${social.label} is not a hex code`).toMatch(/^#[\da-f]{6}$/i);
+    }
+  });
 });
 
 describe("hire me object", () => {