feat(lifecycle): weekly simulation engine [LTV-Pk]

.agent-plan.md

@@ -54,10 +54,13 @@ ALL_CONSTRAINTS/LEAD_SNAPSHOT_FEATURES/CONVERTED_WITHIN_90_DAYS moved to
 consumes bundle files, not internals — no lockstep update needed (heads-up
 issue #8). Next: `LTV-Pg.2` merged (#112). **LTV-M3**: `LTV-Ph` merged (#113); `LTV-Pi`
 (mechanism policies) merged (#116) — **LTV-M3 complete**. **LTV-M4**
-started: `LTV-Pj` (hazard functions — churn_probability with onboarding
-elevation + renewal spike, expansion_probability with health modulation,
-payment_failure_probability; pure/deterministic, Cox-style latent multipliers;
-40 tests) opened as **#117**. Next: `LTV-Pk` (weekly simulation engine).
+`LTV-Pj` (hazard functions) merged (#117). `LTV-Pk` (weekly simulation
+engine — simulate_lifecycle() with per-customer RNG substreams, weekly
+health/monthly invoice cadences, dunning write-off churn, renewal events,
+expansion MRR chains; mechanisms.py base rates ENGINE-CALIBRATED to per-motif
+year-1 churn targets, discharging the #117 calibration obligation; 25 tests)
+opened as **#118** — completes **LTV-M4**. Next: `LTV-M5` (`LTV-Pl` —
+calendar-anchored customer snapshot + pLTV targets).
 
 ---
 

docs/ltv/roadmap.md

@@ -44,7 +44,7 @@ protocol + registry, with the package physically reorganized into
 | `LTV-M1` | Lifecycle schema foundation | `LTV-Pb`, `LTV-Pc` | #104 (Pb) |
 | `LTV-M2` | Generation-scheme architecture + physical reorg | `LTV-Pd`, `LTV-Pe`, `LTV-Pf`, `LTV-Pg` | #107 (Pd), #108 (Pe), #109 (Pf.1), #110 (Pf.2), #111 (Pg.1), #112 (Pg.2) |
 | `LTV-M3` | Customer population + lifecycle world | `LTV-Ph`, `LTV-Pi` | #113 (Ph) |
-| `LTV-M4` | Lifecycle simulation engine | `LTV-Pj`, `LTV-Pk` | #117 (Pj) |
+| `LTV-M4` | Lifecycle simulation engine | `LTV-Pj`, `LTV-Pk` | #117 (Pj), #118 (Pk) |
 | `LTV-M5` | Customer snapshots + pLTV targets (both regimes) | `LTV-Pl`, `LTV-Pm` | |
 | `LTV-M6` | Register LifecycleScheme + recipe + manifest/version | `LTV-Pn`, `LTV-Po` | |
 | `LTV-M7` | Validation + regression-metric calibration | `LTV-Pp` | |
@@ -173,13 +173,13 @@ Total: ~19 PRs across 9 milestones.
 
 ## `LTV-M4` — Lifecycle simulation engine
 
-- [ ] **`LTV-Pj`** — `feat(lifecycle): churn / expansion / payment hazards` (**PR #117**).
+- [x] **`LTV-Pj`** — `feat(lifecycle): churn / expansion / payment hazards` (**PR #117**).
   Weibull churn hazard with renewal-date spike, expansion propensity (the
   heavy-tail generator for pLTV), payment failure + dunning.
   - Tests: hazard shape over tenure, renewal spike, dunning escalation,
     expansion MRR-delta bounds.
   - Labels: `type: feature`, `layer: mechanisms`
-- [ ] **`LTV-Pk`** — `feat(lifecycle): weekly simulation engine`.
+- [ ] **`LTV-Pk`** — `feat(lifecycle): weekly simulation engine` (**PR #118**).
   `simulate_lifecycle()`: weekly loop per customer through `observation_date +
   730d (+ early-regime buffer)` so all three windows are fully simulated (D6);
   emits `subscription_events`, `health_signals`, `invoices`; updates terminal