docs: Update README with Perl script usage

This commit updates the README.md file to include documentation for the new badi-date.pl script. It provides usage instructions and examples for the available command-line options.

README.md

@@ -152,4 +152,24 @@ Output:
 
 ![cli.svg](images/cli.svg)
 
+## Perl Script
+
+A Perl script is available in the `bin` directory to provide a command-line interface for the Baha'i Date API.
+
+### Usage
+
+`./bin/badi-date.pl [options]`
+
+### Options
+
+- `--today`: Get today's Badi date.
+- `--date <YYYY-MM-DD>`: Get the Badi date for a specific date.
+- `--progress`: Show the progress of the current Badi date.
+
+### Examples
+
+`./bin/badi-date.pl --today`
+`./bin/badi-date.pl --date 2024-01-01`
+`./bin/badi-date.pl --progress`
+
 # Last Update: Dec 28, 2025