feat(curator): background skill maintenance (issue #7816)

Adds the Curator — an auxiliary-model background task that periodically
reviews AGENT-CREATED skills and keeps the collection tidy: tracks usage,
transitions unused skills through active → stale → archived, and spawns
a forked AIAgent to consolidate overlaps and patch drift.

Default: enabled, inactivity-triggered (no cron daemon). Runs on CLI
startup and gateway boot when the last run is older than interval_hours
(default 24) AND the agent has been idle for min_idle_hours (default 2).

Invariants (all load-bearing):
- Never touches bundled or hub-installed skills (.bundled_manifest +
  .hub/lock.json double-filter)
- Never auto-deletes — archive only. Archives are recoverable
  via `hermes curator restore <skill>`
- Pinned skills bypass all auto-transitions
- Uses the aux client; never touches the main session's prompt cache

New files:
- tools/skill_usage.py — sidecar .usage.json telemetry, atomic writes,
  provenance filter
- agent/curator.py — orchestrator: config, idle gating, state-machine
  transitions (pure, no LLM), forked-agent review prompt
- hermes_cli/curator.py — `hermes curator {status,run,pause,resume,
  pin,unpin,restore}` subcommand
- tests/tools/test_skill_usage.py — 29 tests
- tests/agent/test_curator.py — 25 tests

Modified files (surgical patches):
- tools/skills_tool.py — bump view_count on successful skill_view
- tools/skill_manager_tool.py — bump patch_count on skill_manage
  patch/edit/write_file/remove_file; forget record on delete
- hermes_cli/config.py — add curator: section to DEFAULT_CONFIG
- hermes_cli/commands.py — add /curator CommandDef with subcommands
- hermes_cli/main.py — register `hermes curator` subparser via
  register_cli() from hermes_cli.curator
- cli.py — /curator slash-command dispatch + startup hook
- gateway/run.py — gateway-boot hook (mirrors CLI)

Validation:
- 54 new tests across skill_usage + curator, all passing in 3s
- 346 tests across all touched files' neighbors green
- 2783 tests across hermes_cli/ + gateway/test_run_progress_topics.py green
- CLI smoke: `hermes curator status/pause/resume` work end-to-end

Companion to PR #16026 (class-first skill review prompt) — together
they form a loop: the review prompt stops near-duplicate skill creation
at the source, and the curator prunes/consolidates what still accumulates.

Refs #7816.

hermes_cli/config.py

@@ -915,6 +915,35 @@ DEFAULT_CONFIG = {
         "guard_agent_created": False,
     },
 
+    # Curator — background skill maintenance.
+    #
+    # Periodically reviews AGENT-CREATED skills (never bundled or
+    # hub-installed) and keeps the collection tidy: marks long-unused skills
+    # as stale, archives genuinely obsolete ones (archive only, never
+    # deletes), and spawns a forked aux-model agent to consolidate overlaps
+    # and patch drift. Runs inactivity-triggered from session start — no
+    # cron daemon.
+    #
+    # See `hermes curator status` for the last run summary.
+    "curator": {
+        "enabled": True,
+        # How long to wait between curator runs (hours).
+        "interval_hours": 24,
+        # Only run when the agent has been idle at least this long (hours).
+        "min_idle_hours": 2,
+        # Mark a skill as "stale" after this many days without use.
+        "stale_after_days": 30,
+        # Archive a skill (move to skills/.archive/) after this many days
+        # without use. Archived skills are recoverable — no auto-deletion.
+        "archive_after_days": 90,
+        # Optional per-task override for the curator's aux model. Leave null
+        # to use Hermes' main auxiliary client resolution.
+        "auxiliary": {
+            "provider": None,
+            "model": None,
+        },
+    },
+
     # Honcho AI-native memory -- reads ~/.honcho/config.json as single source of truth.
     # This section is only needed for hermes-specific overrides; everything else
     # (apiKey, workspace, peerName, sessions, enabled) comes from the global config.