fix(cli): 1.31.1 — reaper no longer blocks the daemon event loop

1.31.0 introduced a session reaper that called execFileSync(ps) once
per registered session every 5s. With many sessions registered, the
daemon's event loop stalled for hundreds of ms — long enough that
incoming /v1/version probes from the CLI timed out against a healthy
daemon and the new service-managed warning fired.

Fix:

- getProcessStartTime is now async (execFile + promisify); never
  blocks the event loop
- New getProcessStartTimes(pids) issues one batched ps for all
  survivors instead of N separate forks. Sweep cost is fixed
  regardless of session count.
- registerSession stays sync; start-time capture is fire-and-forget
- reapDead is now async; the setInterval wrapper voids it so a
  rejected sweep cannot crash the daemon

Behavior is otherwise unchanged from 1.31.0: same 5s cadence, same
PID-reuse guard semantics, same broker-WS teardown via the registry
hook. 83/83 tests still green.

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

apps/cli/package.json

@@ -1,6 +1,6 @@
 {
   "name": "claudemesh-cli",
-  "version": "1.31.0",
+  "version": "1.31.1",
   "description": "Peer mesh for Claude Code sessions — CLI + MCP server.",
   "keywords": [
     "claude-code",