Timeline: place dots by co-op stage at the event date

Each date-field event is now plotted on the lane corresponding to the Framework Stage the co-op was in on the field's stored date, resolved from the activity stream's stage transitions. Date_Opened is pinned to Stage 5 as the journey anchor. Events that pre-date any known transition fall back to the field's section rank so they still surface somewhere. Extracts the STAGE_RANK map (previously inline in ReportView) into lib/stageRank.ts alongside the new buildStageRankAtDate resolver factory.

lib/stageRank.ts

@@ -0,0 +1,50 @@
+import type { ActivitySummary } from "@/types/form";
+
+/**
+ * CiviCRM activity stage values → Framework Stage rank (1..5). "Inquiry"
+ * predates Stage 1 and is conventionally rank 0 (pre-engagement); callers
+ * that render stage lanes 1..5 should treat 0 as "no rank in scope".
+ */
+export const STAGE_RANK: Record<string, number> = {
+  Inquiry: 0,
+  Organizing: 1,
+  Feasibility: 2,
+  "Business feasibility": 3,
+  "Store Implementation": 4,
+  "Stabilize newly opened co-op": 5,
+};
+
+/**
+ * Build a resolver that returns the co-op's Framework Stage rank at a given
+ * point in time, derived from the activity stream. Only activities that
+ * carry a non-empty `stage` value are stage transitions; their stage holds
+ * from that activity's date forward until the next transition.
+ *
+ * Returns `null` when the date precedes any known transition (i.e. we have
+ * no evidence of which stage the co-op was in at that point) — callers can
+ * fall back to a field-section default in that case.
+ */
+export function buildStageRankAtDate(
+  activities: ActivitySummary[]
+): (isoDate: string) => number | null {
+  const transitions = activities
+    .filter(
+      (a): a is ActivitySummary & { stage: string } =>
+        typeof a.stage === "string" && a.stage.length > 0
+    )
+    .map((a) => ({ t: new Date(a.date).getTime(), stage: a.stage }))
+    .filter((tr) => Number.isFinite(tr.t))
+    .sort((a, b) => a.t - b.t);
+
+  return (isoDate: string) => {
+    const t = new Date(isoDate).getTime();
+    if (!Number.isFinite(t)) return null;
+    let last: number | null = null;
+    for (const tr of transitions) {
+      if (tr.t > t) break;
+      const r = STAGE_RANK[tr.stage];
+      if (typeof r === "number") last = r;
+    }
+    return last;
+  };
+}