Consolidate theme toggle styles and update repository references

- Extract duplicated theme-toggle styles into shared mixin (theme-toggle-styles)
- Remove duplicate CSS across privacy.scss, admin.scss, index.scss, and main.scss
- Apply mixin consistently to .theme-toggle, .theme-toggle-admin classes
- Update git repository references from GitHub to git.deco.sh
- Update README.md, privacy.html, and deploy script URLs
- Build optimized CSS with consolidated styles

public/privacy.html

@@ -92,7 +92,7 @@
                 <h2>Contact Information</h2>
                 <p>Questions about this privacy policy or your data?</p>
                 <ul>
-                    <li>Create an issue on our <a href="https://github.com/deco/great-lakes-ice-report" target="_blank">GitHub repository</a></li>
+                    <li>Create an issue on our <a href="https://git.deco.sh/deco/ice" target="_blank">git repository</a></li>
                     <li>Review our <a href="https://www.aclu.org/know-your-rights/immigrants-rights" target="_blank">recommended rights resources</a></li>
                     <li>This is a community tool - please use responsibly</li>
                 </ul>