README.md: apply the confirmed Swarm HTML link fix here too (matching main/dev), and remove the temporary A/B test line.
Same fix as //p4-sdp/dev change 33457 -- site-root-relative /view/ links
instead of plain relative ones, plus the SDP_Developer_Guide filename fix
and missing-paren fix. Applied directly here since this release stream
won't receive it via the normal flow otherwise.
Agent: Claude Code, Model: Claude Sonnet 5 (claude-sonnet-5), operating as bot_Claude_Anthropic.