new /texts page lets a user manage their own texts (list +
create form linking to /texts/{id}); /texts/{id} reuses
text.js for the node tree, with a back link to /texts. home
gains a 'My texts' link in the header. the admin texts page
now sources its cross-user list from /api/texts/all.
apply the page shell to the admin texts page and present each
existing text as a card-link plus the new-text form as a card with
a primary submit button. ids (#texts-list, #newTextName, #submit,
#back) and the name attribute on the input are preserved so the
existing cypress flows continue to work.