Add R5 skip navigation link template and supporting CSS to meet WCAG 2.4.1 Bypass Blocks (A).
- New template: deploy/gitea-a11y/custom/templates/custom/skip_link.tmpl
Provides a "Skip to main content" anchor as the first focusable element.
- Updated deploy/gitea-a11y/custom/public/css/a11y-fixes.css (V5):
Styles for .skip-link, visually hidden off-screen until focus.
- Updated README.md with R5 documentation and activation instructions.
- deploy-gitea-a11y.sh: include R5 in deployed fixes list.
Usage: Insert `{{template "custom/skip_link" .}}` immediately after <body> in custom/header.tmpl.
Targets #545. Part of STEP35 FREE BURN — Gitea-first a11y V1.