Two-direction contract test (tests/website/test_slash_commands_doc_parity.py):
every CommandDef must be documented under its name or an alias, and every
doc table row must resolve to a registered command. Ported from IronClaw's
doc-fact contract tests (nearai/ironclaw#7378), adapted from their clap
--help parser to our COMMAND_REGISTRY single source of truth.
Real drift it caught, fixed here: /loop (alias /proactive) shipped with a
full feature page (user-guide/features/loops.md) and CLI+gateway handlers
but never got a row in the slash-commands reference. Added to both the CLI
Session table and the messaging table, plus the both-surfaces note.
48bd70b586