Add broker REWRITE reference files; governance CLAUDE.md; session-002 handoff
Add doc/broker-rewrite-reference/ with CBD project examples illustrating
the p4broker REWRITE feature: broker config, wssync.py entry point,
and Cbd.py implementation, plus a README summarizing the filter script
protocol (stdin fields, PASS/REJECT/REWRITE output format).
Rewrite ai/CLAUDE.md as durable governance document covering server
topology, DLP notes, workspace patterns, bot ticket management,
and P4Sudo dev architecture.