feat(cli): peer list self-marking + send self-DM guard

closes the "DM looped back to my own inbox" footgun.

what was happening: peer list returns one row per presence,
including the caller's own session AND its sibling sessions.
the cli filtered out the exact-session row but left siblings
unlabeled — copying their pubkey from peer list silently
targeted your own sibling, and the message arrived in "your
own inbox" because the sender was you.

fix is two-part.

(1) peer list — tag rows whose memberPubkey matches the
caller's stable JoinedMesh.pubkey:
  ● displayName (this session) — the exact session running
                                 the cli call
  ● displayName (your other session) — sibling session of
                                       your own member
visually identical otherwise; just the marker.

(2) claudemesh send — refuse a target that exactly matches the
caller's own member pubkey on the mesh, with a hint pointing
at --self for the rare intentional sibling-DM case.

both changes additive — existing scripts that pass display
names or other peers' pubkeys behave identically.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/cli/package.json

@@ -1,6 +1,6 @@
 {
   "name": "claudemesh-cli",
-  "version": "1.16.0",
+  "version": "1.17.0",
   "description": "Peer mesh for Claude Code sessions — CLI + MCP server.",
   "keywords": [
     "claude-code",