Add CONTRIBUTING, Code of Conduct, and issue/PR templates (repo has no .github directory)

[royalpinto007]

What we want

Add CONTRIBUTING.md, CODE_OF_CONDUCT.md, and GitHub issue and pull request templates to this repo.

Why it matters

This repository has no .github/ directory at all. There is no contributing guide, no code of conduct, no issue template, and no PR template. The sibling repository SignalizeAI/SignalizeAI has all of them, so the two halves of the same project currently give contributors completely different experiences.

Concretely, someone who wants to fix a typo on the marketing site today has to reverse engineer from package.json that the checks are npm run lint and npm run build, guess the branch naming convention, and guess whether tests are expected. README.md covers local setup well (env vars, npm run dev, the auth notes) but says nothing about how to contribute a change.

Steps

1. Add CONTRIBUTING.md at the repo root. Mirror the structure of the extension repo's CONTRIBUTING.md so the two feel like one project, and make it accurate for this repo:
   • fork, clone, branch
   • setup pointing at the "Local development" section of README.md, including the .env.local keys (NEXT_PUBLIC_SUPABASE_URL, NEXT_PUBLIC_SUPABASE_ANON_KEY, NEXT_PUBLIC_API_BASE_URL) and the existing .env.example
   • the checks that actually exist here: npm run lint and npm run build. Do not promise a test command, this repo has no test runner configured.
   • a note that Prettier config lives in .prettierrc.json with prettier-plugin-tailwindcss, so class ordering is formatted automatically
   • a pointer to the good first issue label
2. Add CODE_OF_CONDUCT.md. Contributor Covenant 2.1 is fine, use the same contact address as the extension repo.
3. Add .github/ISSUE_TEMPLATE/bug_report.md and .github/ISSUE_TEMPLATE/feature_request.md, and .github/PULL_REQUEST_TEMPLATE.md. Copying the extension repo's versions and adjusting the wording for a web app (browser, route, signed in or out, rather than extension and manifest) is exactly the right amount of work.
4. Link CONTRIBUTING.md from README.md.

Notes

Documentation only, nothing to build or deploy. Keep the tone of the existing docs: short, plain, no filler. If you would rather do this in two PRs (guide first, templates second) that is fine, just say so.

Comment here to claim it. I usually reply within a day.