feat: Add process package to monorepo

- Add `sal-process` package for cross-platform process management.
- Update workspace members in `Cargo.toml`.
- Mark process package as complete in MONOREPO_CONVERSION_PLAN.md
- Remove license information from `mycelium` and `os` READMEs.

process/tests/run_tests.rs

@@ -0,0 +1,251 @@
+use sal_process::{run, run_command, run_silent, RunError};
+use std::env;
+
+#[test]
+fn test_run_simple_command() {
+    let result = run_command("echo hello").unwrap();
+    assert!(result.success);
+    assert_eq!(result.code, 0);
+    assert!(result.stdout.contains("hello"));
+    assert!(result.stderr.is_empty());
+}
+
+#[test]
+fn test_run_command_with_args() {
+    let result = run_command("echo hello world").unwrap();
+    assert!(result.success);
+    assert_eq!(result.code, 0);
+    assert!(result.stdout.contains("hello world"));
+}
+
+#[test]
+fn test_run_silent() {
+    let result = run_silent("echo silent test").unwrap();
+    assert!(result.success);
+    assert_eq!(result.code, 0);
+    assert!(result.stdout.contains("silent test"));
+}
+
+#[test]
+fn test_run_builder_pattern() {
+    let result = run("echo builder test").silent(true).execute().unwrap();
+
+    assert!(result.success);
+    assert_eq!(result.code, 0);
+    assert!(result.stdout.contains("builder test"));
+}
+
+#[test]
+fn test_run_builder_die_false() {
+    let result = run("false") // Command that always fails
+        .die(false)
+        .silent(true)
+        .execute()
+        .unwrap();
+
+    assert!(!result.success);
+    assert_ne!(result.code, 0);
+}
+
+#[test]
+fn test_run_builder_die_true() {
+    // Use a command that will definitely fail
+    let result = run("exit 1") // Script that always fails
+        .die(true)
+        .silent(true)
+        .execute();
+
+    assert!(result.is_err());
+}
+
+#[test]
+fn test_run_multiline_script() {
+    let script = r#"
+        echo "Line 1"
+        echo "Line 2"
+        echo "Line 3"
+    "#;
+
+    let result = run_command(script).unwrap();
+    assert!(result.success);
+    assert_eq!(result.code, 0);
+    assert!(result.stdout.contains("Line 1"));
+    assert!(result.stdout.contains("Line 2"));
+    assert!(result.stdout.contains("Line 3"));
+}
+
+#[test]
+fn test_run_script_with_shebang() {
+    let script = r#"#!/bin/bash
+        echo "Script with shebang"
+        exit 0
+    "#;
+
+    let result = run_command(script).unwrap();
+    assert!(result.success);
+    assert_eq!(result.code, 0);
+    assert!(result.stdout.contains("Script with shebang"));
+}
+
+#[test]
+fn test_run_script_error_handling() {
+    let script = r#"
+        echo "Before error"
+        false
+        echo "After error"
+    "#;
+
+    let result = run(script).silent(true).execute();
+    assert!(result.is_err());
+}
+
+#[test]
+fn test_run_empty_command() {
+    let result = run_command("");
+    assert!(result.is_err());
+    match result.unwrap_err() {
+        RunError::EmptyCommand => {}
+        _ => panic!("Expected EmptyCommand error"),
+    }
+}
+
+#[test]
+fn test_run_nonexistent_command() {
+    let result = run("nonexistent_command_12345").silent(true).execute();
+    assert!(result.is_err());
+}
+
+#[test]
+fn test_run_with_environment_variables() {
+    env::set_var("TEST_VAR", "test_value");
+
+    #[cfg(target_os = "windows")]
+    let script = "echo %TEST_VAR%";
+
+    #[cfg(not(target_os = "windows"))]
+    let script = r#"
+        export TEST_VAR="test_value"
+        echo $TEST_VAR
+    "#;
+
+    let result = run_command(script).unwrap();
+    assert!(result.success);
+    assert!(result.stdout.contains("test_value"));
+
+    env::remove_var("TEST_VAR");
+}
+
+#[test]
+fn test_run_with_working_directory() {
+    // Test that commands run in the current working directory
+    let result = run_command("pwd").unwrap();
+    assert!(result.success);
+    assert!(!result.stdout.is_empty());
+}
+
+#[test]
+fn test_command_result_properties() {
+    let result = run_command("echo test").unwrap();
+
+    // Test all CommandResult properties
+    assert!(!result.stdout.is_empty());
+    assert!(result.stderr.is_empty());
+    assert!(result.success);
+    assert_eq!(result.code, 0);
+}
+
+#[test]
+fn test_run_builder_log_option() {
+    // Test that log option doesn't cause errors
+    let result = run("echo log test")
+        .log(true)
+        .silent(true)
+        .execute()
+        .unwrap();
+
+    assert!(result.success);
+    assert!(result.stdout.contains("log test"));
+}
+
+#[test]
+fn test_run_cross_platform_commands() {
+    // Test commands that work on all platforms
+
+    // Test echo command
+    let result = run_command("echo cross-platform").unwrap();
+    assert!(result.success);
+    assert!(result.stdout.contains("cross-platform"));
+
+    // Test basic shell operations
+    #[cfg(target_os = "windows")]
+    let result = run_command("dir").unwrap();
+
+    #[cfg(not(target_os = "windows"))]
+    let result = run_command("ls").unwrap();
+
+    assert!(result.success);
+}
+
+#[test]
+fn test_run_script_with_variables() {
+    let script = r#"
+        VAR="test_variable"
+        echo "Variable value: $VAR"
+    "#;
+
+    let result = run_command(script).unwrap();
+    assert!(result.success);
+    assert!(result.stdout.contains("Variable value: test_variable"));
+}
+
+#[test]
+fn test_run_script_with_conditionals() {
+    let script = r#"
+        if [ "hello" = "hello" ]; then
+            echo "Condition passed"
+        else
+            echo "Condition failed"
+        fi
+    "#;
+
+    let result = run_command(script).unwrap();
+    assert!(result.success);
+    assert!(result.stdout.contains("Condition passed"));
+}
+
+#[test]
+fn test_run_script_with_loops() {
+    let script = r#"
+        for i in 1 2 3; do
+            echo "Number: $i"
+        done
+    "#;
+
+    let result = run_command(script).unwrap();
+    assert!(result.success);
+    assert!(result.stdout.contains("Number: 1"));
+    assert!(result.stdout.contains("Number: 2"));
+    assert!(result.stdout.contains("Number: 3"));
+}
+
+#[test]
+fn test_run_with_stderr_output() {
+    // Test that stderr field exists and can be accessed
+    let result = run_command("echo test").unwrap();
+    assert!(result.success);
+    // Just verify that stderr field exists and is accessible
+    let _stderr_len = result.stderr.len(); // This verifies stderr field exists
+}
+
+#[test]
+fn test_run_builder_chaining() {
+    let result = run("echo chaining test")
+        .silent(true)
+        .die(true)
+        .log(false)
+        .execute()
+        .unwrap();
+
+    assert!(result.success);
+    assert!(result.stdout.contains("chaining test"));
+}