Implement bd daemons killall and logs (bd-153, bd-152)

Amp-Thread-ID: https://ampcode.com/threads/T-f1cff202-188b-4850-a909-c2750d24ad22
Co-authored-by: Amp <amp@ampcode.com>

internal/daemon/kill_unix.go

@@ -13,3 +13,16 @@ func killProcess(pid int) error {
 	}
 	return nil
 }
+
+func forceKillProcess(pid int) error {
+	if err := syscall.Kill(pid, syscall.SIGKILL); err != nil {
+		return fmt.Errorf("failed to send SIGKILL to PID %d: %w", pid, err)
+	}
+	return nil
+}
+
+func isProcessAlive(pid int) bool {
+	// On Unix, sending signal 0 checks if process exists
+	err := syscall.Kill(pid, 0)
+	return err == nil
+}