Rewrite every v1 document for the native one-install product

[NtrpyDev]

Blocked-by: #47 #48 #49

Goal

Rewrite every public and operator-facing OpenFrag v1 document after the bundled recorder, native GTK4 client, and documentation research are settled.

Required work

1. Rewrite the root README as the concise product landing page and verified first-run path.
2. Rewrite About and application metadata for the native desktop product.
3. Write task-oriented installation and upgrade instructions for GitHub static, AUR, Fedora 43, and Fedora 44 without any separate recorder installation.
4. Document system requirements, supported and untested environments, desktop portals, graphics and media libraries, codecs, audio, Steam and Counter-Strike requirements, and data locations.
5. Document the three-process architecture, Unix-socket boundary, local-only privacy model, threat model, Game State Integration trust boundary, capture supervision, and why subprocess isolation is intentional.
6. Rewrite setup, Doctor, troubleshooting, recovery, uninstall, data preservation, and known-limitations guidance.
7. Rewrite development, testing, contributing, release, provenance, GPL source availability, fork maintenance, third-party notices, support matrix, and release notes.
8. Remove or archive every stale reference to a browser dashboard, localhost web UI, arbitrary recorder path, native-versus-Flatpak recorder choice, and separate GPU Screen Recorder installation.
9. Add link, terminology, stale-claim, command, package-content, and no-em-dash checks to the optimized suite.
10. Render or inspect every user-visible Markdown and application metadata surface before publication.

Acceptance criteria

• A repository-wide documentation inventory maps every user-visible surface to an owner and verification command.
• No v1 instruction requires a browser or a separately installed recorder.
• Every command and path is exercised against the exact release candidate where automation is possible.
• Claims about support, privacy, security, and compatibility link to current evidence.
• The README gives a new user the product value, requirements, one correct install path, first launch, and next documentation links without burying caveats or duplicating reference material.
• The complete documentation suite fails on broken internal links, stale product terminology, missing required sections, unsupported claims, or incomplete licensing and provenance.