/guida now serves a static app/static/guida.html placeholder instead of
docs/guida-utente.md, which sidesteps the known Docker gap (docs/ was never
COPYed into the image). Added a matching /report-bug placeholder route and
pointed the navbar's bug icon at it instead of the unset GitHub issues URL,
with an outline circle + exclamation mark to match the help icon's style.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
