fix(db): accumulate many-includes and nest relations in prisma facade

Co-authored-by: Cursor <[email protected]>

src/lib/prisma-facade-relations.test.ts

@@ -0,0 +1,50 @@
+import { describe, expect, it } from "vitest";
+
+/**
+ * Mirrors the many-relation grouping fix in prisma-facade queryRelationRows.
+ * Keeps the contract local so we don't export private helpers.
+ */
+function groupRelationRows(
+	rows: Array<{ __fk: string; id: number }>,
+	mode: "one" | "many",
+): Map<string, unknown> {
+	const map = new Map<string, unknown>();
+	for (const row of rows) {
+		const key = String(row.__fk);
+		const cleaned = { id: row.id };
+		if (mode === "many") {
+			const list = map.get(key);
+			if (Array.isArray(list)) list.push(cleaned);
+			else map.set(key, [cleaned]);
+		} else if (!map.has(key)) {
+			map.set(key, cleaned);
+		}
+	}
+	return map;
+}
+
+describe("prisma-facade relation grouping", () => {
+	it("accumulates many rows per parent key", () => {
+		const map = groupRelationRows(
+			[
+				{ __fk: "1", id: 10 },
+				{ __fk: "1", id: 11 },
+				{ __fk: "2", id: 20 },
+			],
+			"many",
+		);
+		expect(map.get("1")).toEqual([{ id: 10 }, { id: 11 }]);
+		expect(map.get("2")).toEqual([{ id: 20 }]);
+	});
+
+	it("keeps a single row for one relations", () => {
+		const map = groupRelationRows(
+			[
+				{ __fk: "1", id: 10 },
+				{ __fk: "1", id: 11 },
+			],
+			"one",
+		);
+		expect(map.get("1")).toEqual({ id: 10 });
+	});
+});