Wire up direct-rates column; remove dormant pause-on-block flow

Direct-rates sub-row in Market View was dead: the frontend filters
competitors on direct_hotel_id but /matrix and /hotels never returned it.
Add direct_hotel_id to both queries (+ HotelResponse), and only render the
"Direct" sub-row when a hotel actually has a non-null direct rate (was
rendering all-dashes on an empty {} object).

Remove the pause-on-block flow entirely — dormant since rotate-on-block
replaced it (nothing set booking_scraper_paused=true after set_scraper_paused
was dropped): is_scraper_paused, /config/unpause, the /scrape paused guard,
ScraperStatusResponse.paused/pause_until, and the frontend Paused badge +
Unpause button. Trim now-unused datetime import.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/src/pages/Settings.tsx

@@ -536,7 +536,6 @@ function SystemTab({ config, isLoading }: { config: SystemConfig | undefined; is
 
   const displayKeys = [
     'booking_scraper_enabled',
-    'booking_scraper_paused',
     'booking_scraper_backend',
     'booking_scraper_daily_time',
     'booking_proxy_enabled',