Visual templates: use the project's name and fitting sample content instead of 'Acme'

[ckryptickunal]

Found in the U5 usability test (research/U5-usability-student.md, research/U5-usability-designer.md). engine.py show swaps in the project name, but the templates in skills/opendesigner/assets/templates/ still hard-code 'Acme' and business sample text, and some labels are technical. Add template fields for the project name and a surface-appropriate sample (club site, admin table, finance dashboard, guide), and use plain labels (see _coordination/lanes/U4-rules.md).