Show errors and warnings on the display (_ERROR, _WARN)

action_raise_error aborts while the macro renders, so an M117 in the same
macro never ran and errors such as the RESUME lane check only reached the
console. messages.cfg adds _ERROR (M117, then raise in a separate macro)
and _WARN (RESPOND TYPE=error + M117); all errors and warnings use them.
PAUSE shows AFC's error as the pause reason; RESUME, CANCEL_PRINT and
PRINT_WARMUP clear the display.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

macros/afc/purge_check.cfg

@@ -162,7 +162,7 @@ gcode:
         {% set verdict = 'FAIL: ' ~ failed|join(', ') if failed else ('OK' if checked else 'NOTHING CHECKED') %}
         RESPOND MSG="PURGE_CHECK {lane}: {motion}; {press} -> {verdict}"
         {% if failed and cfg.mode == "enforce" %}
-            RESPOND TYPE=error MSG="PURGE_CHECK: {lane} {failed|join(', ')} - check extruder and lane"
+            _WARN MSG="PURGE_CHECK: {lane} {failed|join(', ')} - check extruder and lane" DISPLAY="Purge check failed: {lane}, paused"
             SET_GCODE_VARIABLE MACRO=_PURGE_CHECK_CFG VARIABLE=last_failed VALUE=True
             PAUSE                       ; no effect while already paused (resume purge): see _RESUME_PURGE_VERIFY
         {% endif %}