Add organization landing page

[Copilot]

Created README.md as organization profile landing page for the usestring GitHub organization.

Changes

• Welcome & Mission: Brief introduction positioning usestring as a string manipulation tooling organization
• Projects Section: Navigation point to organization repositories
• Contributing Guidelines: Standard fork-branch-PR workflow instructions
• Contact: Organization links and issue tracking reference

The landing page provides first-time visitors with clear context about the organization's purpose and how to engage with its projects.

Original prompt

create repo landing page

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[EllAchE]

Closing this in favour of #3, which supersedes it. Two independent problems, neither fixable by editing the copy:

1. The positioning is hallucinated. The description here — "an organization focused on building tools and libraries for string manipulation, processing, and utilities," with a mission to provide "string utilities across different programming languages and platforms" — appears to be inferred from the org's name. String builds a web access / web data API: one request against any URL, with anti-bot handling, CAPTCHA solving and JS rendering handled server-side, billed only on successful delivery. Nothing in this repo is about string manipulation. Merging it would have made the org's most prominent public surface wrong about what the company does.

2. It targets a path that renders nowhere. GitHub builds an org profile only from a repo named exactly .github, at exactly profile/README.md (docs). This repo was named .usestring — the user-profile convention, where the repo matches the username — which an org gets no special treatment for. So a root README.md here was never going to appear on github.com/usestring; merging this would have changed nothing visible.

#3 renames the repo to .github, adds profile/README.md, and sources every claim from the site, the portal docs, and the repos' own READMEs rather than from the org name.