feat(v0.6.5): execution-grounded skill-utility report (adam-skill-utility)

Ranks skills by good:bad outcome co-occurrence (Wilson LB + lift vs
baseline) over the journal's active_skills payloads — the SkillsInjector
(arXiv 2605.29794) execution-grounded utility signal Δ(s), computed from
data already collected, no training.

- reuses adam-score NEGATIVE_SIGNAL_TYPES + entrySeverity (single source of truth)
- registered in install.sh helper-script copy loop
- /reflect pre-step surfaces worst below-baseline skills to the USER as
  advisory (co-occurrence != causation; not fed to the analyst's proposal machinery)
- Test 119 added; full suite 141/141 green

skills/adam-self-improvement/SKILL.md

@@ -81,6 +81,14 @@ node ~/.claude/adam/scripts/adam-batch.mjs --input /tmp/adam-windowed-journal.js
 
 This groups entries by (signal_type, cluster_key) and reports per-batch metadata including `has_context_window` (whether transcript evidence is attached). If the script fails: log stderr, pass `null` to the analyst (graceful degradation — analyst falls back to raw journal clustering).
 
+**Skill utility** (execution-grounded selection signal, in the spirit of SkillsInjector arXiv 2605.29794 — utility Δ(s), not surface match): compute per-skill good:bad outcome ratios over the windowed journal:
+
+```bash
+node ~/.claude/adam/scripts/adam-skill-utility.mjs --input /tmp/adam-windowed-journal.jsonl --json > /tmp/adam-skill-utility.json 2> /tmp/adam-skill-utility.log
+```
+
+This ranks skills by how often they co-occur with positive (`task_completed`, `clean_recovery`, `correction_free_streak`) vs negative outcome events, surfacing skills below the baseline positive rate (with sufficient sample) — advisory candidates for description disambiguation or archival. **CO-OCCURRENCE, NOT CAUSATION**: display the worst 3 below-baseline skills (`lift < 0`, not low-sample) to the *user* as a one-line advisory before listing proposals (e.g. `skill-utility: chezmoi 9% pos n=85, ghostty-config 14% pos n=50, …`). Do NOT feed this into the analyst's proposal machinery or auto-draft skill-archival from it — the human decides. If the script fails: log stderr, skip (best-effort).
+
 ### 2. Dispatch the analyst (two-stage pipeline)
 
 MOSS §3.3: "A single prompt asked to diagnose, plan, implement, verify, and decide overloads context and produces lower-quality output than a sequenced flow." The analyst is dispatched in two stages with a validation gate between them.