chore: initialize repository with deployment baseline

backend/src/lib/prisma-json.ts

@@ -0,0 +1,48 @@
+import type { Prisma } from "@prisma/client";
+
+export function toPrismaJsonValue(value: unknown): Prisma.InputJsonValue {
+  if (value === null) {
+    return "null";
+  }
+
+  if (typeof value === "string" || typeof value === "boolean") {
+    return value;
+  }
+
+  if (typeof value === "number") {
+    return Number.isFinite(value) ? value : String(value);
+  }
+
+  if (typeof value === "bigint") {
+    return value.toString();
+  }
+
+  if (value instanceof Date) {
+    return value.toISOString();
+  }
+
+  if (value instanceof Error) {
+    return {
+      name: value.name,
+      message: value.message,
+      stack: value.stack ?? ""
+    };
+  }
+
+  if (Array.isArray(value)) {
+    return value.map((item) => toPrismaJsonValue(item));
+  }
+
+  if (typeof value === "object") {
+    const output: Record<string, Prisma.InputJsonValue> = {};
+
+    for (const [key, raw] of Object.entries(value as Record<string, unknown>)) {
+      if (raw === undefined) continue;
+      output[key] = toPrismaJsonValue(raw);
+    }
+
+    return output;
+  }
+
+  return String(value);
+}