Multi-region monitoring, subdomain discovery and optional regions

#New

Multi-region monitoring: one watched page can now monitor several regions at once — price, title, stock, description, keywords each as an independent region. Each region extracts, baselines and double-confirms on its own, while sharing a single fetch (one page visit regardless of region count); changes confirmed in the same round are merged into one notification. Existing watches become a "primary region" automatically with unchanged behavior. Up to 10 regions per page.
Subdomain asset discovery: Sites → "Subdomain discovery" — enter a root domain to find subdomains that once had certificates issued, from public Certificate Transparency logs. This often surfaces forgotten staging machines or legacy sites that aren't in your DNS records. Lookups are passive reads of public logs and never touch the candidate hosts; select candidates to add them as sites under existing rules (paused by default). Quota: 20 lookups per tenant and 200 platform-wide per 24-hour window.
Optional regions: for content that legitimately comes and goes — subtitles, promo lines — mark the region "allow missing (optional region)". When the page is healthy but the element is absent, the region records an "absent" baseline instead of an extraction error; appearing, changing and disappearing later still notify under double-confirmation. CSS / XPath text regions only.

The site traffic Weekly report in the inbox now opens a full detail page: per-site pageviews, visitors, sessions, bounce rate, plus top pages, referrers and events (previously opening only marked the message read).

The discovery rate-limit hint now says the window is a fixed 24 hours.
UI polish: discovery forms sit side-by-side on desktop and wrap on narrow screens; member form controls align; push-device rows wrap correctly on mobile instead of forcing horizontal scroll.