feat(gui): warn when the hotend rack inventory falls short of the sliced plate

Follow-up to the rack-aware pre-print checks: after the blocking checks
pass, warn (without disabling Send) when the plate needs more matching
hotends than the rack printer currently holds - suggesting rack setup,
a nozzle info refresh, or a re-slice to avoid filament waste - or when
the only matches rely on unreliable nozzle information.

Text-only warning rows; this message board has no refresh or
don't-show-again buttons.

src/slic3r/GUI/PrePrintChecker.hpp

@@ -97,6 +97,8 @@ enum PrintDialogStatus : unsigned int {
     PrintStatusToolHeadCoolingFanWarning,
     PrintStatusRackNozzleMappingWarning,
     PrintStatusFilaSwitcherSlicingNotMatch,
+    PrintStatusRackNozzleNumUnmeetWarning,
+    PrintStatusHasUnreliableNozzleWarning,
     PrintStatusPrinterWarningEnd,
 
     // Warnings for filament