Bug Fixes & Stability Improvements

A round of fixes across the platform to keep things running smoothly:

• Perplexity tracking is back on schedule after Perplexity changed its search box on October 31.
• Content Gap analyses that hit a search error now fail and can be retried, instead of saving 0% coverage.
• The AI insights overview compares the same crawler groups across both periods, so its changes no longer jump.
• The Offsite Mentions source filter no longer lists social channels, which have their own pages.
• Project viewers no longer see API key secrets or the API keys page.
• Sign-in codes are tighter: only the latest code works, and deactivated users can't request one.
• YouTube citations with no video description load again.
• The Instagram post sheet keeps its tabs on screen for long captions.
• Stacked bar charts render in solid colors again.
• Small layout fixes: Brand Book field spacing, analytics filter rows on narrow screens, long template and project names, and the sitemap setup card when its check fails.
• The resolved Perplexity outage banner is gone.