v4.7.2 — Mail that nobody reads is now visible

Patch from the relay message audit of 2026-09-24 (Hermes, Antigravity,
zcode, Claude): messages were parked for days with nobody knowing, and the
tool meant to answer "why doesn't X answer" hung instead.

Fixed

• relay doctor executed arbitrary binaries. The version probe ran
  <exe> -c "import conscio; ..." for EVERY process in /proc, before even
  checking whether it was Conscio. zcode, antigravity and gnome-keyring-daemon
  were spawned with -c, forking daemons outlived the 5s kill (9 stray
  processes measured), and doctor hung for minutes. Only Conscio processes
  are inspected now, and only Python interpreters are probed (for claude,
  -c is --continue). Deleted binaries are never executed.
• Broadcast fed dead peers. A card silent for 20 days still received
  every broadcast. Local peers silent past 3 days are skipped and listed in
  the new skipped field. Paired remotes are never judged: their age is
  the pairing time.
• Direct send to a dormant peer said only "ok". It still delivers (the
  sender named the peer), but now returns a warning with how long it has
  been silent.
• directory.prune never ran in production. It existed and was
  tested, but nothing called it. It now runs on the send path with the rest
  of retention, never collects a paired remote, and re-reads the card
  right before deleting it (an agent that came back is not collected).
• Phantom space from an unsubstituted plugin variable. Codex installed
  the Claude Code plugin and ran its .mcp.json verbatim: it does not
  substitute ${CLAUDE_PLUGIN_DATA}, so conscio-mcp received the literal
  string and created a ${CLAUDE_PLUGIN_DATA}/space directory relative to
  its working directory — inside the repo, untracked, one git add . away
  from committing a database. conscio-mcp now refuses a --storage that
  still contains ${VAR} or $VAR: it exits 2, names the variable, and
  creates nothing. Hosts that substitute the variable (Claude Code, zcode)
  are unaffected.

Added

• relay doctor reports mailboxes. For each local agent: unconsumed
  messages, the oldest one's age, by sender; messages parked in the spool;
  DORMANT state. It also warns about spools with mail but no card (nobody
  will ingest them). Read-only: mailbox.waiting opens the db with
  mode=ro, never creates a schema, never quarantines.

Changed

• relay_broadcast returns skipped alongside sent/errors.

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