Refresh Linux and Omarchy documentation and fork additions

[Gberfield]

The README and desktop guides still treated Television as Mac-only, while the Linux guide mixed current installation steps with historical releases and conflicting version statements. This update documents the fork's Linux/Omarchy behavior and separates source changes from published payloads.

• Add a fork overview and maintained documentation index covering Linux packaging, tray/Hide, canvas handling, durable theme synchronization, Sponsors, the Markdown table fix and upstream tracking.
• Rewrite Linux installation, connection, troubleshooting, updates and build guidance; preserve historical acceptance in a separate release-history guide.
• Update the administrator and desktop guides for downstream Linux support without implying publication of the public guide.
• Document activated tracking, manual detection/validation, retained ancestry and Eastern Time scheduling; expand theme health/repair instructions.

Validation: canonical documentation/spec reference suite passed (8 tests); 57 local links and anchors in changed/new documents resolve; git diff --check passed. Current main, Linux 1.4.27 release assets and Actions permissions were verified against GitHub. No application code changed; no full runtime/build acceptance is claimed.

Draft for human review: administrator-guide procedures require human review under specs/arch/cli/admin-guide.md. This PR does not publish desktop payloads, deploy the public guide or change the running installation.