PWA + UI overhaul: sidebar friends, messaging features, service worker and manifest#13

reodesureodesu wants to merge 7 commits into

codex/improve-app-uireodesureodesu/LINE:codex/improve-app-uifrom

codex/fix-new-registration-error-and-add-features-opu5rareodesureodesu/LINE:codex/fix-new-registration-error-and-add-features-opu5raCopy head branch name to clipboard