feat(srs): switch ladder to +3/+7 and enforce rest‑day logic

apps/api/src/stats.ts

@@ -11,6 +11,7 @@ import {
   campaignDay,
   campaignWeek,
   isoWeek,
+  STAGES,
   streak,
 } from "./srs.ts";
 
@@ -59,7 +60,8 @@ export async function buildStats(db: D1Database, today: string): Promise<object>
   const { results: ladderRows } = await db
     .prepare("SELECT stage, COUNT(*) AS n FROM problems GROUP BY stage")
     .all<{ stage: string; n: number }>();
-  const ladder: Record<string, number> = { new: 0, "+2": 0, "+5": 0, "+10": 0, retired: 0 };
+  // Every rung is present even at zero: the page's bar list is this object.
+  const ladder: Record<string, number> = Object.fromEntries(STAGES.map((s) => [s, 0]));
   for (const row of ladderRows) ladder[row.stage] = row.n;
 
   // gates rows are keyed by ISO week (that's the digest/gate contract), but