Adapt economics dashboard to sole-member zero-cost reality

Update membership, revenue, and cost registries to one active member with
no running costs. Refresh dashboard report and tests for €8.99 revenue and
100% gross margin.

projects/coulomb-pricing/data/membership.json

@@ -1,40 +1,16 @@
 {
   "version": 1,
-  "snapshot_date": "2026-06-21",
+  "snapshot_date": "2026-06-22",
   "members": [
     {
-      "id": "member-001",
+      "id": "member-founder",
       "external_id": null,
       "status": "active",
       "joined_at": "2025-11-03",
       "plan_id": "flat-899-eur-monthly",
-      "source": "seed"
-    },
-    {
-      "id": "member-002",
-      "external_id": null,
-      "status": "active",
-      "joined_at": "2026-01-15",
-      "plan_id": "flat-899-eur-monthly",
-      "source": "seed"
-    },
-    {
-      "id": "member-003",
-      "external_id": null,
-      "status": "active",
-      "joined_at": "2026-03-28",
-      "plan_id": "flat-899-eur-monthly",
-      "source": "seed"
-    },
-    {
-      "id": "member-004",
-      "external_id": null,
-      "status": "churned",
-      "joined_at": "2025-08-10",
-      "churned_at": "2026-02-01",
-      "plan_id": "flat-899-eur-monthly",
-      "source": "seed"
+      "source": "manual",
+      "note": "Sole active member (founder)"
     }
   ],
-  "note": "Seed data for Sprint 1; replaced by Bubble importer in Sprint 2"
+  "note": "Current reality: one active member. Bubble importer (Sprint 2) will sync live data."
 }