Closes #3991

Adds HTTP Basic Authentication support for published pages and project-level .wsauth rules.

This introduces a new @webstudio-is/wsauth package that owns the generic authentication format logic: parsing, validation, serialization, route matching, resource generation, and request authentication. The current supported method is basic, with the package structured so additional auth methods can be added later.

Builder changes include:

• Page Settings now has an Authentication section for per-page Basic Auth credentials.
• Project Settings now has an Authentication section for editing .wsauth route rules.
• Page Settings was split into section-specific files with focused tests.
• Auth UI shows Pro badges/info tooltips but remains editable.
• Publishing to custom domains is blocked on plans without allowAuth when either page auth or project auth is configured.
• ProBadge now renders as a real pricing link and uses improved text alignment.

Build/publish changes include:

• CLI prebuild generates and merges .wsauth entries.
• Published app templates enforce auth for HTML/XML routes.
• Generated auth resources are shared between build output and runtime.