Extend theming from 3 CSS variables (primary colors only) to 14
configurable properties covering colors, fonts, borders, and shape.
All values are optional with sensible defaults.
- New _theme.html include replaces duplicated inline injection
- Wire theme include into all 7 templates (base, login, dashboard,
catalog, admin_tables, activity_center, corporate_memory)
- Conditional font loading: skip default Inter when custom font_url set
- Config.theme_overrides() classmethod generates CSS variable dict
- Visual theme-reference.html guide for instance configurators
- Document all theme keys in instance.yaml.example
