feat: Add support for new OS package

- Add a new `sal-os` package containing OS interaction utilities.
- Update workspace members to include the new package.
- Add README and basic usage examples for the new package.

os/tests/rhai/01_file_operations.rhai

@@ -0,0 +1,111 @@
+// 01_file_operations.rhai
+// Tests for file system operations in the OS module
+
+// Custom assert function
+fn assert_true(condition, message) {
+    if !condition {
+        print(`ASSERTION FAILED: ${message}`);
+        throw message;
+    }
+}
+
+// Create a test directory structure
+let test_dir = "rhai_test_fs";
+let sub_dir = test_dir + "/subdir";
+
+// Test mkdir function
+print("Testing mkdir...");
+let mkdir_result = mkdir(test_dir);
+assert_true(exist(test_dir), "Directory creation failed");
+print(`✓ mkdir: ${mkdir_result}`);
+
+// Test nested directory creation
+let nested_result = mkdir(sub_dir);
+assert_true(exist(sub_dir), "Nested directory creation failed");
+print(`✓ mkdir (nested): ${nested_result}`);
+
+// Test file_write function
+let test_file = test_dir + "/test.txt";
+let file_content = "This is a test file created by Rhai test script.";
+let write_result = file_write(test_file, file_content);
+assert_true(exist(test_file), "File creation failed");
+print(`✓ file_write: ${write_result}`);
+
+// Test file_read function
+let read_content = file_read(test_file);
+assert_true(read_content == file_content, "File content doesn't match");
+print(`✓ file_read: Content matches`);
+
+// Test file_size function
+let size = file_size(test_file);
+assert_true(size > 0, "File size should be greater than 0");
+print(`✓ file_size: ${size} bytes`);
+
+// Test file_write_append function
+let append_content = "\nThis is appended content.";
+let append_result = file_write_append(test_file, append_content);
+let new_content = file_read(test_file);
+assert_true(new_content == file_content + append_content, "Appended content doesn't match");
+print(`✓ file_write_append: ${append_result}`);
+
+// Test copy function
+let copied_file = test_dir + "/copied.txt";
+let copy_result = copy(test_file, copied_file);
+assert_true(exist(copied_file), "File copy failed");
+print(`✓ copy: ${copy_result}`);
+
+// Test mv function
+let moved_file = test_dir + "/moved.txt";
+let mv_result = mv(copied_file, moved_file);
+assert_true(exist(moved_file), "File move failed");
+assert_true(!exist(copied_file), "Source file still exists after move");
+print(`✓ mv: ${mv_result}`);
+
+// Test find_file function
+let found_file = find_file(test_dir, "*.txt");
+assert_true(found_file.contains("test.txt") || found_file.contains("moved.txt"), "find_file failed");
+print(`✓ find_file: ${found_file}`);
+
+// Test find_files function
+let found_files = find_files(test_dir, "*.txt");
+assert_true(found_files.len() == 2, "find_files should find 2 files");
+print(`✓ find_files: Found ${found_files.len()} files`);
+
+// Test find_dir function
+let found_dir = find_dir(test_dir, "sub*");
+assert_true(found_dir.contains("subdir"), "find_dir failed");
+print(`✓ find_dir: ${found_dir}`);
+
+// Test find_dirs function
+let found_dirs = find_dirs(test_dir, "sub*");
+assert_true(found_dirs.len() == 1, "find_dirs should find 1 directory");
+print(`✓ find_dirs: Found ${found_dirs.len()} directories`);
+
+// Test chdir function
+// Save current directory path before changing
+let chdir_result = chdir(test_dir);
+print(`✓ chdir: ${chdir_result}`);
+
+// Change back to parent directory
+chdir("..");
+
+// Test rsync function (if available)
+let rsync_dir = test_dir + "/rsync_dest";
+mkdir(rsync_dir);
+let rsync_result = rsync(test_dir, rsync_dir);
+print(`✓ rsync: ${rsync_result}`);
+
+// Test delete function
+let delete_file_result = delete(test_file);
+assert_true(!exist(test_file), "File deletion failed");
+print(`✓ delete (file): ${delete_file_result}`);
+
+// Clean up
+delete(moved_file);
+delete(sub_dir);
+delete(rsync_dir);
+delete(test_dir);
+assert_true(!exist(test_dir), "Directory deletion failed");
+print(`✓ delete (directory): Directory cleaned up`);
+
+print("All file system tests completed successfully!");