docs: Add user instructions for STAC_ITEM_LIMIT env variable

Author: Yuri Zmytrakov

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ### Added 
 
+- Added default environment variable `STAC_ITEM_LIMIT` to SFEOS for result limiting of returned items and STAC collections
 - Added comprehensive index management system with dynamic selection and insertion strategies for improved performance and scalability [#405](https://github.com/stac-utils/stac-fastapi-elasticsearch-opensearch/pull/405)
 - Added `ENABLE_DATETIME_INDEX_FILTERING` environment variable to enable datetime-based index selection using collection IDs. When enabled, the system creates indexes with UUID-based names and manages them through time-based aliases. Default is `false`. [#405](https://github.com/stac-utils/stac-fastapi-elasticsearch-opensearch/pull/405)
 - Added `DATETIME_INDEX_MAX_SIZE_GB` environment variable to set maximum size limit in GB for datetime-based indexes. When an index exceeds this size, a new time-partitioned index will be created. Note: add +20% to target size due to ES/OS compression. Default is `25` GB. Only applies when `ENABLE_DATETIME_INDEX_FILTERING` is enabled. [#405](https://github.com/stac-utils/stac-fastapi-elasticsearch-opensearch/pull/405)

README.md

@@ -226,6 +226,7 @@ You can customize additional settings in your `.env` file:
 | `RAISE_ON_BULK_ERROR`        | Controls whether bulk insert operations raise exceptions on errors. If set to `true`, the operation will stop and raise an exception when an error occurs. If set to `false`, errors will be logged, and the operation will continue. **Note:** STAC Item and ItemCollection validation errors will always raise, regardless of this flag. | `false` | Optional |
 | `DATABASE_REFRESH`           | Controls whether database operations refresh the index immediately after changes. If set to `true`, changes will be immediately searchable. If set to `false`, changes may not be immediately visible but can improve performance for bulk operations. If set to `wait_for`, changes will wait for the next refresh cycle to become visible. | `false` | Optional |
 | `ENABLE_TRANSACTIONS_EXTENSIONS` | Enables or disables the Transactions and Bulk Transactions API extensions. If set to `false`, the POST `/collections` route and related transaction endpoints (including bulk transaction operations) will be unavailable in the API. This is useful for deployments where mutating the catalog via the API should be prevented. | `true` | Optional |
+| `STAC_ITEM_LIMIT` | Sets the environment variable for result limiting to SFEOS for the number of returned items and STAC collections. | `10` | Optional |
 
 > [!NOTE]
 > The variables `ES_HOST`, `ES_PORT`, `ES_USE_SSL`, `ES_VERIFY_CERTS` and `ES_TIMEOUT` apply to both Elasticsearch and OpenSearch backends, so there is no need to rename the key names to `OS_` even if you're using OpenSearch.