Added SSE client that connects to oven.aesthetic.computer/papers-build to show real-time build progress. Shows scrolling log lines with timestamps (like OS boot telemetry), progress bar, stage label, and percentage. Auto-hides when no build is running, auto-reloads page after successful build to pick up new PDFs. Logs panel is collapsible by clicking the header. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>