Rename sili → StILi: update all identifiers and documentation

Rename sili → StILi: update all identifiers and documentation

The project identifier is renamed from the informal "sili" to "StILi"
((St)atic (I)mport site (Li)berator), which makes the purpose explicit
and sounds like the German/Italian word for "style".

- pom.xml: artifactId maven-siteliberator-skin → maven-stili-skin,
  updated name, description, and SCM URLs
- site.vm: HTML IDs sili-title/sili-body/sili-json → stili-*
- import scripts: stili-json pattern, mention StILi skin in usage text,
  add --base option to import-in-astro.sh (general-purpose support)
- CLAUDE.md: rewritten with name origin, community architecture model,
  and updated stili-* references throughout

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>