Groom wizard steps 1-15: critique/harden/polish pass

- [P0] CrematoriumStep: Fix <option> → <MenuItem> in priority select
- [P1] All form steps: Add aria-busy={loading} + loading guard on submit
- [P1] Error messages: Replace color="error" (red) with copper
  (var(--fa-color-text-brand)) across ProvidersStep, PackagesStep,
  VenueStep, CrematoriumStep, CemeteryStep, CoffinsStep, PaymentStep
- [P2] IntroStep: "Has the person died?" → "Has this person passed away?"
- [P2] DateTimeStep: "About the person who died" → "who has passed"
- [P2] ProvidersStep: "Showing results from X" → "X providers found"
- [P2] Empty states: Add guidance text for ProvidersStep, PackagesStep,
  VenueStep, CoffinsStep empty results

Steps 4, 13, 15 passed with no issues.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/components/pages/PackagesStep/PackagesStep.tsx

@@ -221,7 +221,11 @@ export const PackagesStep: React.FC<PackagesStepProps> = ({
 
       {/* Error message */}
       {error && (
-        <Typography variant="body2" color="error" sx={{ mb: 2 }} role="alert">
+        <Typography
+          variant="body2"
+          sx={{ mb: 2, color: 'var(--fa-color-text-brand)' }}
+          role="alert"
+        >
           {error}
         </Typography>
       )}
@@ -262,9 +266,12 @@ export const PackagesStep: React.FC<PackagesStepProps> = ({
 
         {packages.length === 0 && (
           <Box sx={{ py: 6, textAlign: 'center' }}>
-            <Typography variant="body1" color="text.secondary">
+            <Typography variant="body1" color="text.secondary" sx={{ mb: 1 }}>
               No packages match the selected budget range.
             </Typography>
+            <Typography variant="body2" color="text.secondary">
+              Try selecting &quot;All packages&quot; to see the full range.
+            </Typography>
           </Box>
         )}
       </Box>