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.

text/tests/template_tests.rs

@@ -15,7 +15,7 @@ use tempfile::NamedTempFile;
 #[test]
 fn test_template_builder_basic_string_variable() {
     // Create a temporary template file
-    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let temp_file = NamedTempFile::new().expect("Failed to create temp file");
     let template_content = "Hello {{name}}!";
     fs::write(temp_file.path(), template_content).expect("Failed to write template");
 
@@ -30,7 +30,7 @@ fn test_template_builder_basic_string_variable() {
 
 #[test]
 fn test_template_builder_multiple_variables() {
-    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let temp_file = NamedTempFile::new().expect("Failed to create temp file");
     let template_content = "{{greeting}} {{name}}, you have {{count}} messages.";
     fs::write(temp_file.path(), template_content).expect("Failed to write template");
 
@@ -47,7 +47,7 @@ fn test_template_builder_multiple_variables() {
 
 #[test]
 fn test_template_builder_different_types() {
-    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let temp_file = NamedTempFile::new().expect("Failed to create temp file");
     let template_content = "String: {{text}}, Int: {{number}}, Float: {{decimal}}, Bool: {{flag}}";
     fs::write(temp_file.path(), template_content).expect("Failed to write template");
 
@@ -65,8 +65,9 @@ fn test_template_builder_different_types() {
 
 #[test]
 fn test_template_builder_array_variable() {
-    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
-    let template_content = "Items: {% for item in items %}{{item}}{% if not loop.last %}, {% endif %}{% endfor %}";
+    let temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let template_content =
+        "Items: {% for item in items %}{{item}}{% if not loop.last %}, {% endif %}{% endfor %}";
     fs::write(temp_file.path(), template_content).expect("Failed to write template");
 
     let items = vec!["apple", "banana", "cherry"];
@@ -81,7 +82,7 @@ fn test_template_builder_array_variable() {
 
 #[test]
 fn test_template_builder_add_vars_hashmap() {
-    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let temp_file = NamedTempFile::new().expect("Failed to create temp file");
     let template_content = "{{title}}: {{description}}";
     fs::write(temp_file.path(), template_content).expect("Failed to write template");
 
@@ -101,7 +102,7 @@ fn test_template_builder_add_vars_hashmap() {
 #[test]
 fn test_template_builder_render_to_file() {
     // Create template file
-    let mut template_file = NamedTempFile::new().expect("Failed to create template file");
+    let template_file = NamedTempFile::new().expect("Failed to create template file");
     let template_content = "Hello {{name}}, today is {{day}}.";
     fs::write(template_file.path(), template_content).expect("Failed to write template");
 
@@ -121,8 +122,9 @@ fn test_template_builder_render_to_file() {
 
 #[test]
 fn test_template_builder_conditional() {
-    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
-    let template_content = "{% if show_message %}Message: {{message}}{% else %}No message{% endif %}";
+    let temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let template_content =
+        "{% if show_message %}Message: {{message}}{% else %}No message{% endif %}";
     fs::write(temp_file.path(), template_content).expect("Failed to write template");
 
     // Test with condition true
@@ -148,7 +150,7 @@ fn test_template_builder_conditional() {
 
 #[test]
 fn test_template_builder_loop_with_index() {
-    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let temp_file = NamedTempFile::new().expect("Failed to create temp file");
     let template_content = "{% for item in items %}{{loop.index}}: {{item}}\n{% endfor %}";
     fs::write(temp_file.path(), template_content).expect("Failed to write template");
 
@@ -164,7 +166,7 @@ fn test_template_builder_loop_with_index() {
 
 #[test]
 fn test_template_builder_nested_variables() {
-    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let temp_file = NamedTempFile::new().expect("Failed to create temp file");
     let template_content = "User: {{user.name}} ({{user.email}})";
     fs::write(temp_file.path(), template_content).expect("Failed to write template");
 
@@ -183,7 +185,7 @@ fn test_template_builder_nested_variables() {
 
 #[test]
 fn test_template_builder_missing_variable_error() {
-    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let temp_file = NamedTempFile::new().expect("Failed to create temp file");
     let template_content = "Hello {{missing_var}}!";
     fs::write(temp_file.path(), template_content).expect("Failed to write template");
 
@@ -196,7 +198,7 @@ fn test_template_builder_missing_variable_error() {
 
 #[test]
 fn test_template_builder_invalid_template_syntax() {
-    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let temp_file = NamedTempFile::new().expect("Failed to create temp file");
     let template_content = "Hello {{unclosed_var!";
     fs::write(temp_file.path(), template_content).expect("Failed to write template");
 
@@ -215,7 +217,7 @@ fn test_template_builder_nonexistent_file() {
 
 #[test]
 fn test_template_builder_empty_template() {
-    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let temp_file = NamedTempFile::new().expect("Failed to create temp file");
     fs::write(temp_file.path(), "").expect("Failed to write empty template");
 
     let result = TemplateBuilder::open(temp_file.path())
@@ -228,7 +230,7 @@ fn test_template_builder_empty_template() {
 
 #[test]
 fn test_template_builder_template_with_no_variables() {
-    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let temp_file = NamedTempFile::new().expect("Failed to create temp file");
     let template_content = "This is a static template with no variables.";
     fs::write(temp_file.path(), template_content).expect("Failed to write template");
 
@@ -242,7 +244,7 @@ fn test_template_builder_template_with_no_variables() {
 
 #[test]
 fn test_template_builder_complex_report() {
-    let mut temp_file = NamedTempFile::new().expect("Failed to create temp file");
+    let temp_file = NamedTempFile::new().expect("Failed to create temp file");
     let template_content = r#"
 # {{report_title}}