Add FeedConfig and SitemapConfig structs to config.rs
with enabled: bool (default true) for opt-out control.
Refactor ConfigContext: flat nested_nav bool replaced
with nested nav: NavContext { nested, toc } to mirror
site.toml [nav] table structure.
Remove standalone base_url template variable; use
config.base_url as single source of truth with
trailing-slash trimming in ConfigContext::from().
Add section template fallback: try section/<type>.html,
fall back to section/default.html for unknown types.
Delete section/features.html (duplicate of default.html)
and homepage.html (dead code, never referenced).
Update base.html for new variable names.
Self-documenting docs site built with sukr itself (dogfooding):
- docs/site.toml with sukr.io base URL
- docs-specific templates with sidebar navigation
- Dark theme CSS, responsive layout
- Documentation: getting-started, configuration, features
Also: improved error chaining for better template debugging
