refactor(css): extract inline styles to css classes and update README with technical details

feat(ui): remove redundant navbar from start page

feat(ui): unify navigation bar across all pages and disable profile link on start page

feat(ui): add floating info button to reopen modal and enforce single-session flow

fix(ui): reset intro modal visibility with v2 key and add localized tooltip to name input

fix(ui): enhance modal styling, navbar color, form validation and session logic

feat(ui): add welcome modal with portfolio project details

style: improved card alignment and responsiveness in templates

refactor(start): improve profile creation form layout and toggle logic

feat(genres): add and alphabetically sort extended list of book genres in start and profile forms

feat(start): allow toggling between new profile creation and existing profiles list

feat: add custom stylesheet for improved UI

feat(app): adds start route