feat(core): support cooperative SIGINT cancellation

brush-builtins/src/kill.rs

@@ -119,6 +119,15 @@ impl builtins::Command for KillCommand {
                 }
             } else {
                 let pid = brush_core::int_utils::parse(pid_or_job_spec.as_str(), 10)?;
+                let is_self_signal =
+                    i32::try_from(std::process::id()).is_ok_and(|current_pid| current_pid == pid);
+
+                if is_self_signal && context.shell.traps().handles(trap_signal) {
+                    if let Ok(signal_number) = i32::try_from(trap_signal) {
+                        context.params.request_host_signal(signal_number);
+                        return Ok(ExecutionResult::success());
+                    }
+                }
 
                 // It's a pid.
                 sys::signal::kill_process(pid, trap_signal)?;

brush-core/src/commands.rs

@@ -614,13 +614,16 @@ pub(crate) fn execute_external_command(
             cmd.process_group(0);
             if child_stdin_is_terminal {
                 cmd.take_foreground();
+            } else {
+                cmd.reset_job_control_signals();
             }
         }
     } else {
         // We need to join an established process group.
         if let Some(pgid) = process_group_id {
             cmd.process_group(pgid);
         }
+        cmd.reset_job_control_signals();
     }
 
     // When tracing is enabled, report.