feat(bandit): promote egreedy-v2 (D=12, profile features) as active policy (#99)

Offline sim gate passed — egreedy-v2 mean reward −0.629 vs egreedy-v1 −0.642
(5 users × 20 rounds, rule judge, seed 42). v2 wins 3/5 personas.

- recommender.ts: switch remotePolicy() to /score/egreedy/v2
- recommender.ts: switch sendRewardWithRetry() to /reward/egreedy/v2 with
  profile_features payload so the ridge update uses the full D=12 vector
- recommender.ts: re-fetch profile at feedback time (TTL-cached, near-instant)
- ADR-0012: status Accepted → Promoted, promotion record appended

Shadow entry egreedy-v2-shadow kept in registry (active: false) for rollback.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/adr/0012-egreedy-v2-profile-features.md

@@ -1,7 +1,7 @@
 # ADR-0012 — ε-greedy v2: profile features in the bandit (D=7→12)
 
-**Status:** Accepted  
+**Status:** Promoted  
-**Date:** 2026-04-25  
+**Date:** 2026-04-25 (accepted) / 2026-04-26 (promoted)  
 **Issue:** #99
 
 ## Context
@@ -106,3 +106,19 @@ projecting theta without the corresponding `A` matrix cannot be done correctly.
 the D=12 target in the issue spec and complicates the sim comparison. Deferred.
 
 **In-place v1 promotion without shadow** — violates ADR-0002.
+
+## Promotion record (2026-04-26)
+
+Offline sim (`runner.py --policies egreedy-v1 egreedy-v2 --judge rule --n-users 5 --n-rounds 20 --seed 42`):
+
+| policy | total reward | mean reward | pulls |
+|--------|-------------|-------------|-------|
+| egreedy-v1 | −64.20 | −0.6420 | 100 |
+| egreedy-v2 | −62.90 | −0.6290 | 100 |
+
+**Gate passed** (v2 mean ≥ v1 mean). Per-persona: v2 wins deadline-driven, evening-relaxed, low-priority-first; v1 wins consistent-responder, overdue-ignorer.
+
+Changes applied:
+- `recommender.ts` `remotePolicy()`: `/score/egreedy` → `/score/egreedy/v2`
+- `recommender.ts` `sendRewardWithRetry()`: `/reward/egreedy` → `/reward/egreedy/v2`, added `profile_features` to payload
+- Shadow entry `egreedy-v2-shadow` left in registry (`active: false`) for rollback.

services/api/src/routes/recommender.ts

@@ -47,7 +47,8 @@ export const _clearCandidateCacheForTests = () => {
 // Shadow-policy registry
 // ---------------------------------------------------------------------------
 const shadowPolicies = new Map<string, { active: boolean }>([
-  // egreedy-v2 (D=12, profile features) — disabled until sim gate per ADR-0012
+  // egreedy-v2 promoted to active policy (ADR-0012). Shadow entry kept for
+  // rollback toggle; leave disabled in normal operation.
   ['egreedy-v2-shadow', { active: false }],
 ]);
 
@@ -101,9 +102,9 @@ async function remotePolicy(
     profile_features: profile,
   };
 
-  // Active policy: egreedy-v1 (selected over linucb-v1 after offline sim — ADR-0007)
+  // Active policy: egreedy-v2 (promoted from shadow after offline sim — ADR-0012)
   try {
-    const res = await fetch(`${config.ML_SERVING_URL}/score/egreedy`, {
+    const res = await fetch(`${config.ML_SERVING_URL}/score/egreedy/v2`, {
       method: 'POST',
       headers: { 'Content-Type': 'application/json' },
       body: JSON.stringify(body),
@@ -111,7 +112,7 @@ async function remotePolicy(
     });
     if (!res.ok) return null;
     const data = (await res.json()) as { tip_id: string; score: number };
-    return { tipId: data.tip_id, score: data.score, policy: 'egreedy-v1' };
+    return { tipId: data.tip_id, score: data.score, policy: 'egreedy-v2' };
   } catch {
     return null;
   }
@@ -371,6 +372,7 @@ async function sendRewardWithRetry(
   tipId: string,
   reward: number,
   features: TipCandidate['features'],
+  profile: Profile,
 ): Promise<void> {
   const body = JSON.stringify({
     user_id: userId,
@@ -378,11 +380,12 @@ async function sendRewardWithRetry(
     reward,
     features,
     day_of_week: new Date().getDay(),
+    profile_features: profile,
   });
 
   for (let attempt = 1; attempt <= 3; attempt++) {
     try {
-      const res = await fetch(`${config.ML_SERVING_URL}/reward/egreedy`, {
+      const res = await fetch(`${config.ML_SERVING_URL}/reward/egreedy/v2`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body,
@@ -463,7 +466,9 @@ router.post('/tip/:id/feedback', requireAuth, async (req: AuthenticatedRequest,
   });
 
   if (candidate) {
-    sendRewardWithRetry(req.userId!, tipId, reward, candidate.features);
+    // Re-fetch profile for the v2 ridge update; TTL cache makes this near-instant.
+    const profile = await getProfile(req.userId!);
+    sendRewardWithRetry(req.userId!, tipId, reward, candidate.features, profile);
   }
 
   // Delegate action to the owning signal source (e.g. mark done in Todoist)