feat(admin): ActiveSync ops health badges on device admin

[TDannhauer]

Parent

Epic: horde/ActiveSync#99
Depends on: horde/Core#216
Design: horde/ActiveSync doc/ops-monitor.md (§7, Issue E)

Summary

Extend existing admin/activesync.php in horde/base (no new app):

• Status strip counters: active / stuck / wipe-pending / blocked
• Device list: activity age, health badge, signal chips (FSR, HB), log link when known
• Collection detail: annotate stuck collections with reason
• Reuse Core SnapshotService — do not reimplement heuristics in the admin script

Acceptance

• Gated by horde:administration:activesync
• Existing wipe / block / reset / account-wipe unchanged
• New _() strings updated in all locales (+ .mo)
• Full page reload sufficient for v1 (no SPA; auto-refresh optional later)

Notes

CLI remains the live watch surface; Web is fleet overview next to admin actions.

[TDannhauer]

Implementation is ready in #161. It reuses horde/Core#229 for fleet counters, device and collection signals, activity ages, log hints, and explanatory tooltips while preserving existing admin actions. All 42 locale catalogs are included.