chore(readme): add pagination + subgroups related documentation

Author: meeghele

README.md

@@ -15,7 +15,9 @@ A Python command-line tool that automates the process of cloning or fetching all
 ## Features
 
 - **Complete namespace cloning**: Clone all repositories under a specified GitLab namespace, including all nested subgroups
+- **Recursive subgroup discovery**: Automatically discovers and processes deeply nested subgroups with intelligent queueing
 - **Smart sync**: If a repository is not cloned already, it will be cloned; if it exists, it will be fetched
+- **Optimized pagination**: Configurable API pagination with retry logic for large namespaces
 - **Exclusion patterns**: Option to exclude specific subgroups or projects based on name patterns
 - **Dry-run mode**: List all repositories without actually cloning or fetching them
 - **Flexible destination**: Configurable destination path for cloned repositories
@@ -62,6 +64,7 @@ Set your GitLab token using one of these methods:
 | `-d` | `--dry-run` | List repositories without clone/fetch |
 | `-e` | `--exclude` | Pattern to exclude from subgroups and projects |
 | | `--clone-method` | Clone method: `https` or `ssh` (default: `https`) |
+| | `--per-page` | Number of items per page for GitLab API calls (default: 100, max: 100) |
 | `-h` | `--help` | Show help message and exit |
 
 ## Examples