feat(api): complete phase 9 mobile contracts

app/api/v1/health/route.ts

@@ -0,0 +1,27 @@
+import { apiV1Error, apiV1Success } from "@/server/api/v1/responses";
+import { checkReadiness } from "@/server/db/health";
+import { DomainError } from "@/server/domain/errors";
+
+export const runtime = "nodejs";
+export const dynamic = "force-dynamic";
+
+export function GET() {
+  const readiness = checkReadiness();
+  const checkedAt = new Date().toISOString();
+
+  if (!readiness.ok) {
+    return apiV1Error(
+      new DomainError(
+        "SERVICE_UNAVAILABLE",
+        "Instance henüz isteklere hazır değil.",
+        { checks: readiness.checks, checkedAt },
+      ),
+    );
+  }
+
+  return apiV1Success({
+    status: "ok",
+    checks: readiness.checks,
+    checkedAt,
+  });
+}