fix(cli): production-grade peer disambiguation (alpha.42)

Three bugs compounding when multiple peers share a display name:

1. list_peers (MCP + CLI) truncated pubkey to 12 hex chars with an
   ellipsis. A truncated pubkey cannot be used as a routing key, so
   the caller had no way to disambiguate visually.

2. send_message required the full 64-hex pubkey and refused prefix
   input, forcing callers to rely on --json output to get a full key.

3. Name-based resolution returned the first exact match without
   filtering the caller's own session — so "send to <my-own-name>"
   would bounce against the broker's self-send guard when another
   session of the same user was the intended target.

Fixes:
- list_peers now prints 16-char pubkey prefix labelled "pubkey: …"
  (MCP) and appends it to CLI output
- send_message accepts any 8–64 hex-char prefix and resolves against
  live peer lists across joined meshes; unique match routes, multi-
  match returns a disambiguation error listing each candidate's
  displayName + pubkey + cwd
- Name matches now skip the caller's own session pubkey; multiple
  same-named matches fail loudly with a copy-pasteable pubkey
  disambiguation hint instead of silently picking one
- Full 64-char pubkeys without a live match still queue at the
  broker (preserves offline-delivery semantics)

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

apps/cli/package.json

@@ -1,6 +1,6 @@
 {
   "name": "claudemesh-cli",
-  "version": "1.0.0-alpha.41",
+  "version": "1.0.0-alpha.42",
   "description": "Peer mesh for Claude Code sessions — CLI + MCP server.",
   "keywords": [
     "claude-code",