Two performance fixes for browser hanging during active agent work:
1. SSE padding (8KB per event) now only applied when Cloudflare tunnel is
active — direct/Tailscale connections skip the padding entirely. Previously
every broadcast event got 8KB of comment padding even on local connections,
causing 40-160KB/s of wasted bandwidth during active subagent work.
2. Subagent window content renders (tool_call, progress, message, tool_result)
now debounced at 100ms per agent via scheduleSubagentWindowRender(). Previously
each SSE event triggered an immediate DOM rewrite, causing 10-30+ rewrites/sec
that starved the terminal rendering pipeline.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
