feat: add integration tests and runnable examples

Add 91 integration tests (all #[ignore]) mirroring the JavaScript SDK's
integration test suite. Tests cover all endpoints: ping, apps, fields,
records, files, lists, and reports with success, auth, access, and
not-found scenarios.

Add 7 runnable examples (cargo run --example <name>) for quick manual
smoke testing against a real Onspring instance.

Both use env vars (API_BASE_URL, SANDBOX_API_KEY, TEST_*) matching the
JavaScript SDK setup.

Also rename crate to onspring-api-sdk-rust with [lib] name = "onspring"
so imports remain `use onspring::*`.

tests/integration_reports.rs

@@ -0,0 +1,124 @@
+mod integration_common;
+
+use integration_common::*;
+use onspring::{DataFormat, PagingRequest, ReportDataType};
+
+#[tokio::test]
+#[ignore]
+async fn get_report_should_return_report() {
+  let client = build_client();
+  let report_id = required_env_i32("TEST_REPORT");
+
+  let report = client.get_report(report_id, None, None).await.unwrap();
+
+  let columns = report.columns.unwrap();
+  assert!(!columns.is_empty());
+
+  let rows = report.rows.unwrap();
+  assert!(!rows.is_empty());
+
+  for row in &rows {
+    assert!(row.record_id.unwrap() > 0);
+    assert!(!row.cells.as_ref().unwrap().is_empty());
+  }
+}
+
+#[tokio::test]
+#[ignore]
+async fn get_report_with_chart_data_should_return_data() {
+  let client = build_client();
+  let report_id = required_env_i32("TEST_REPORT_WITH_CHART_DATA");
+
+  let report = client
+    .get_report(
+      report_id,
+      Some(DataFormat::Raw),
+      Some(ReportDataType::ChartData),
+    )
+    .await
+    .unwrap();
+
+  assert!(!report.columns.unwrap().is_empty());
+  assert!(!report.rows.unwrap().is_empty());
+}
+
+#[tokio::test]
+#[ignore]
+async fn get_report_should_fail_for_chart_data_on_non_chart_report() {
+  let client = build_client();
+  let report_id = required_env_i32("TEST_REPORT");
+
+  let result = client
+    .get_report(
+      report_id,
+      Some(DataFormat::Raw),
+      Some(ReportDataType::ChartData),
+    )
+    .await;
+  assert!(result.is_err());
+}
+
+#[tokio::test]
+#[ignore]
+async fn get_report_should_fail_with_invalid_api_key() {
+  let client = build_client_with_key("invalid");
+  let result = client.get_report(1, None, None).await;
+  assert!(result.is_err());
+}
+
+#[tokio::test]
+#[ignore]
+async fn get_report_should_fail_when_not_found() {
+  let client = build_client();
+  let result = client.get_report(0, None, None).await;
+  assert!(result.is_err());
+}
+
+#[tokio::test]
+#[ignore]
+async fn list_reports_should_return_reports() {
+  let client = build_client();
+  let app_id = required_env_i32("TEST_SURVEY_ID");
+
+  let response = client.list_reports(app_id, None).await.unwrap();
+
+  assert!(response.total_records.unwrap() > 0);
+  let items = response.items.unwrap();
+  assert!(!items.is_empty());
+
+  for report in &items {
+    assert!(report.id > 0);
+    assert!(report.app_id > 0);
+    assert!(report.name.is_some());
+  }
+}
+
+#[tokio::test]
+#[ignore]
+async fn list_reports_should_fail_with_invalid_api_key() {
+  let client = build_client_with_key("invalid");
+  let result = client.list_reports(1, None).await;
+  assert!(result.is_err());
+}
+
+#[tokio::test]
+#[ignore]
+async fn list_reports_should_fail_when_no_access() {
+  let client = build_client();
+  let app_id = required_env_i32("TEST_APP_ID_NO_ACCESS");
+  let result = client.list_reports(app_id, None).await;
+  assert!(result.is_err());
+}
+
+#[tokio::test]
+#[ignore]
+async fn list_reports_should_fail_with_invalid_page_size() {
+  let client = build_client();
+  let app_id = required_env_i32("TEST_SURVEY_ID");
+  let paging = PagingRequest {
+    page_number: 1,
+    page_size: 1001,
+  };
+  let result = client.list_reports(app_id, Some(paging)).await;
+  assert!(result.is_err());
+}