feat: add run replay for archetype effectiveness analysis

- archeflow-decision.sh records decision points during runs
- archeflow-replay.sh: timeline, whatif, compare commands
- What-if replay with adjustable archetype weights
- /af-replay skill for interactive use
- Tests in archeflow-replay.bats

skills/using-archeflow/SKILL.md

@@ -7,7 +7,7 @@ description: Use at session start when implementing features, reviewing code, de
 
 On activation, print ONE line then proceed silently:
 ```
-archeflow v0.8.0 · 23 skills · <domain> domain
+archeflow v0.9.0 · 24 skills · <domain> domain
 ```
 Domain auto-detected: `writing` if `colette.yaml` exists, `research` if paper/thesis files, `code` otherwise.
 
@@ -46,6 +46,7 @@ Do NOT use for: single-line fixes, questions, reading/exploring, config tweaks,
 | `/af-memory` | Cross-run lesson memory |
 | `/af-fanout` | Colette book fanout via agents |
 | `/af-dag` | DAG of current/last run |
+| `/af-replay <run_id>` | Decision timeline + weighted what-if on recorded events |
 
 ## Mini-Reflect Fallback