feat(curator): show most-used and least-used skills in hermes curator status (#18033)

Alongside the existing 'least recently used' section, surface two more
rankings so users can see which of their agent-created skills actually
get exercised:

- 'most used (top 5)' — sorted by use_count descending. Hidden when every
  skill has use_count=0 (noise suppression on fresh installs).
- 'least used (top 5)' — sorted by use_count ascending. Always shown
  when the catalog is non-empty.

use_count started tracking real agent skill activation in PR #17932
(bump_use wired into skill_view tool + slash invocation + --skill
preload), so these rankings are now meaningful.

Tests: 3 new in tests/hermes_cli/test_curator_status.py — happy path
with mixed use_counts, zero-use suppression of the most-used section,
and the no-skills clean-empty case.

hermes_cli/curator.py

@@ -108,6 +108,49 @@ def _cmd_status(args) -> int:
                 f"last_activity={last}"
             )
 
+    # Show top 5 most-active and least-active skills by activity_count
+    # (use + view + patch). This is a different signal from
+    # least-recently-active: activity_count reflects frequency,
+    # last_activity_at reflects recency. A skill touched 30 times a year
+    # ago is high-frequency but stale; a skill touched once yesterday is
+    # recent but low-frequency. Both can matter.
+    active_all = by_state.get("active", [])
+    if active_all:
+        most_active = sorted(
+            active_all,
+            key=lambda r: (r.get("activity_count") or 0, r.get("last_activity_at") or ""),
+            reverse=True,
+        )[:5]
+        if most_active and (most_active[0].get("activity_count") or 0) > 0:
+            print("\nmost active (top 5):")
+            for r in most_active:
+                last = _fmt_ts(r.get("last_activity_at"))
+                print(
+                    f"  {r['name']:40s}  "
+                    f"activity={r.get('activity_count', 0):3d}  "
+                    f"use={r.get('use_count', 0):3d}  "
+                    f"view={r.get('view_count', 0):3d}  "
+                    f"patches={r.get('patch_count', 0):3d}  "
+                    f"last_activity={last}"
+                )
+
+        least_active = sorted(
+            active_all,
+            key=lambda r: (r.get("activity_count") or 0, r.get("last_activity_at") or ""),
+        )[:5]
+        if least_active:
+            print("\nleast active (top 5):")
+            for r in least_active:
+                last = _fmt_ts(r.get("last_activity_at"))
+                print(
+                    f"  {r['name']:40s}  "
+                    f"activity={r.get('activity_count', 0):3d}  "
+                    f"use={r.get('use_count', 0):3d}  "
+                    f"view={r.get('view_count', 0):3d}  "
+                    f"patches={r.get('patch_count', 0):3d}  "
+                    f"last_activity={last}"
+                )
+
     return 0