New sign in and sign up (v0.7)

We rebuilt the account flow from scratch. Sign in and sign up have their own pages, sessions refresh automatically as you browse, and Google sign-in lands you in the dashboard in one click.

Signing into Last Price is now a first-class experience instead of a detour. The old `/login` route is gone and everything redirects to the new `/sign-in` and `/sign-up` pages.

One-click Google sign-in on both pages

Forgot-password and reset-password flows wired end to end

Sessions refresh in the background so deep links into the dashboard resume cleanly after a tab has been idle

Sign-up form labels its fields explicitly so browser password managers stop autofilling company name into the email field

Same look and feel as the dashboard, with the LastPriceLogo squircle in the sidebar on desktop and the header on mobile