refactor: Harden and improve SSH agent module

- Add extensive security validations for SSH agent
- Implement robust `ssh-agent` auto-start script
- Enhance `sshagent` operations with improved error handling
- Revamp `sshagent` test suite for comprehensive coverage
- Update `sshagent` README with detailed documentation

lib/osal/sshagent/factory.v

@@ -27,7 +27,7 @@ pub fn new(args_ SSHAgentNewArgs) !SSHAgent {
 }
 
 pub fn loaded() bool {
-	mut agent := new() or { panic(err) }
+	mut agent := new() or { return false }
 	return agent.active
 }