Add Contributing + Community sections to README.md

[nora-weisser]

Goal

Add "Contributing" and "Community" sections to README.md so newcomers have a clear on-ramp.

Scope

• Short intro tying the repo to Women Coding Community.
• Link CONTRIBUTING.md, CODE_OF_CONDUCT.md, and the issue tracker.
• Reinforce that tests/.env must be created locally and real credentials must never be committed.
• Optional: status / license badges at the top.

Acceptance criteria

• README has a Contributing section linking CONTRIBUTING.md
• README has a Community section tying the repo to WCC
• All added links resolve

Depends on #ISSUE_1 (CONTRIBUTING.md) and #ISSUE_2 (CODE_OF_CONDUCT.md).