feat(activesync): horde-activesync top watch monitor

[TDannhauer]

Parent

Epic: horde/ActiveSync#99
Depends on: summary/show CLI issue in this repo
Design: horde/ActiveSync doc/ops-monitor.md (§6.1, Issue D)

Summary

horde-activesync top — live / refreshable fleet view (“top-like”) as a standalone horde/base bin subcommand (not hordectl).

horde-activesync top [--watch[=SEC]] [--active-within=SEC]
  [--user=] [--device=] [--health=] [--stuck-only]
  [--sort=] [--format=table|json] [--limit=N]

Columns (v1): USER DEVICE TYPE VER AGE HB FSR HEALTH SIGNALS

Acceptance

• Usable over SSH during Ping/Sync soak
• --watch refresh loop (plain reprint OK for v1; alt-buffer optional)
• --format=json implies one-shot (no watch chrome)
• Graceful error when ActiveSync disabled / unavailable
• Filters: stuck-only, user, device, health

Notes

Read-only. Large fleets: document cost of per-device SyncCache load; rely on --active-within / --limit.

Supersedes

horde/hordectl#21 (wrong home — closed)