feat(curator): make skill consolidation opt-in (prune stays default-on) (#47840)

The curator now defaults to prune-only: the deterministic inactivity pass
(mark stale / archive long-unused skills) still runs whenever the curator is
enabled, but the opinionated LLM umbrella-building consolidation fork is OFF
by default.

- agent/curator.py: add DEFAULT_CONSOLIDATE=False + get_consolidate(); gate
  the forked aux-model review in run_curator_review behind it (new consolidate
  param, None=read config). When off, the LLM pass is skipped entirely (no
  aux-model cost); the run is still recorded and reported.
- config.py: add curator.consolidate (default false); v29->v30 migration seeds
  the key for existing installs without clobbering a user-set value.
- hermes_cli/curator.py: 'hermes curator run --consolidate' override; status
  shows consolidate state; prune-only notice on run.
- docs + tests.

website/docs/user-guide/features/curator.md

@@ -31,8 +31,12 @@ If you want to see what the curator *would* do before it runs for real, run `her
 
 A run has two phases:
 
-1. **Automatic transitions** (deterministic, no LLM). Skills unused for `stale_after_days` (30) become `stale`; skills unused for `archive_after_days` (90) are moved to `~/.hermes/skills/.archive/`.
-2. **LLM review** (single aux-model pass, `max_iterations=8`). The forked agent surveys the agent-created skills, can read any of them with `skill_view`, and decides per-skill whether to keep, patch (via `skill_manage`), consolidate overlapping ones, or archive via the terminal tool. Consolidation treats a skill as a full package: if a skill has `references/`, `templates/`, `scripts/`, `assets/`, or relative links to those paths, the curator must either keep it standalone, re-home the needed support files and rewrite paths, or archive the entire package unchanged — not flatten only `SKILL.md` into another skill's `references/` file.
+1. **Automatic transitions** (deterministic, no LLM). Skills unused for `stale_after_days` (30) become `stale`; skills unused for `archive_after_days` (90) are moved to `~/.hermes/skills/.archive/`. This is the always-on pruning behavior — it runs whenever the curator is enabled, with no aux-model cost.
+2. **LLM consolidation** (single aux-model pass, `max_iterations=8`) — **OFF by default**. When `curator.consolidate: true`, the forked agent surveys the agent-created skills, can read any of them with `skill_view`, and decides per-skill whether to keep, patch (via `skill_manage`), consolidate overlapping ones into class-level umbrellas, or archive via the terminal tool. Consolidation treats a skill as a full package: if a skill has `references/`, `templates/`, `scripts/`, `assets/`, or relative links to those paths, the curator must either keep it standalone, re-home the needed support files and rewrite paths, or archive the entire package unchanged — not flatten only `SKILL.md` into another skill's `references/` file.
+
+:::info Consolidation is opt-in
+By default the curator only **prunes** — the deterministic inactivity pass marks skills stale and archives long-unused ones. The opinionated LLM **consolidation** pass (umbrella-building, merging overlapping skills) is off by default because it costs aux-model tokens on every run and makes broad structural changes to your library. Turn it on with `curator.consolidate: true`, or run it once on demand with `hermes curator run --consolidate`.
+:::
 
 Pinned skills are off-limits to both the curator's auto-transitions and the agent's own `skill_manage` tool. See [Pinning a skill](#pinning-a-skill) below.
 
@@ -47,10 +51,11 @@ curator:
   min_idle_hours: 2
   stale_after_days: 30
   archive_after_days: 90
+  consolidate: false           # LLM umbrella-building pass — opt-in (prune-only by default)
   prune_builtins: true         # archive unused bundled built-in skills too (hub skills always exempt)
 ```
 
-To disable entirely, set `curator.enabled: false`.
+To disable entirely, set `curator.enabled: false`. To keep the always-on pruning but opt into LLM consolidation, set `curator.consolidate: true`.
 
 ### Running the review on a cheaper aux model
 
@@ -85,8 +90,9 @@ Earlier releases used a one-off `curator.auxiliary.{provider,model}` block. That
 
 ```bash
 hermes curator status         # last run, counts, pinned list, LRU top 5
-hermes curator run            # trigger a review now (blocks until the LLM pass finishes)
-hermes curator run --background  # fire-and-forget: start the LLM pass in a background thread
+hermes curator run            # trigger a run now (blocks until done). Prune-only unless curator.consolidate: true
+hermes curator run --consolidate # force the LLM consolidation pass on for this run, overriding the config default
+hermes curator run --background  # fire-and-forget: start the run in a background thread
 hermes curator run --dry-run  # preview only — report without any mutations
 hermes curator backup         # take a manual snapshot of ~/.hermes/skills/
 hermes curator rollback       # restore from the newest snapshot