- Remove FORUM_CSS_DEFAULT/KODAMA2 and _forum_css() from forum handlers
- Add FORUM_CSS constant to templates.py with layout-only forum CSS
- Inject forum CSS into any template's <head> via wrap_page()
- Add forum layout styles to kodama2.html theme
- Update database custom template
- Replace Google Fonts with system font stacks across all themes
- Add Referrer-Policy, X-Content-Type-Options, X-Frame-Options, CSP headers
- Add rel="noreferrer noopener" on all outbound links
- Add no-referrer and dns-prefetch-control meta tags to all themes
- Clean tracking params on outbound links from trusted/remote sources
- Remove Google domains from CSP whitelists