Dashboard UI overhaul: inline feed details, TLD filtering, status improvements

- Feed details now expand inline instead of navigating to new page
- Add TLD section headers with domains sorted by TLD then name
- Add TLD filter button to show/hide domain sections by TLD
- Feed status behavior: pass creates account, hold crawls only, skip stops, drop cleans up
- Auto-follow new accounts from directory account (1440.news)
- Fix handle derivation (removed duplicate .1440.news suffix)
- Increase domain import batch size to 100k
- Various bug fixes for account creation and profile updates

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

main.go

@@ -56,7 +56,10 @@ func main() {
 	// Publish loop (background) - autopublishes items for approved feeds
 	go crawler.StartPublishLoop()
 
-	// Crawl loop (background)
+	// Domain check loop (background) - verifies approved domains are reachable
+	go crawler.StartDomainCheckLoop()
+
+	// Crawl loop (background) - crawls checked domains for feeds
 	go crawler.StartCrawlLoop()
 
 	// Wait for shutdown signal