Upgraded to TypeScript 7

Upgraded the underlying TypeScript tooling to its newest major version, which compiles and checks code much faster behind the scenes. No visible changes for you.
Upgraded the underlying JavaScript runtime and package manager to their latest versions, for better performance and security. No visible changes for you.
Laid groundwork for signing in once and staying signed in across Land Your Home's different sites in the future. No visible changes for you yet.
Renamed some internal project files as part of preparing to split Land Your Home into separate sites in the future. No visible changes for you.
Moved sign-in and sign-up onto their own dedicated internal service, another step toward Land Your Home running as separate sites in the future. No visible changes for you — the same sign-in and sign-up pages work exactly as before.