feat(FN-2669): consolidate mobile fullscreen modal styles

- Move the WorkflowStepManager mobile modal sizing rules into the primary max-width 768px block
- Expand mobile fullscreen behavior to enforce viewport height, remove borders, and zero border radius
- Add mobile wrapping support for step card title/action rows and remove the duplicate trailing media block

packages/dashboard/app/components/WorkflowStepManager.css

@@ -401,6 +401,17 @@
 }
 
 @media (max-width: 768px) {
+  .workflow-step-manager-modal {
+    width: 100%;
+    max-width: 100%;
+    height: 100vh;
+    height: 100dvh;
+    max-height: 100vh;
+    max-height: 100dvh;
+    border-radius: 0;
+    border: none;
+  }
+
   .wfm-body {
     flex: 1;
     min-height: 0;
@@ -428,6 +439,10 @@
     gap: var(--space-sm);
   }
 
+  .wfm-step-card-title-row {
+    flex-wrap: wrap;
+  }
+
   .wfm-step-card-actions {
     flex-wrap: wrap;
     margin-left: 0;
@@ -462,13 +477,3 @@
     padding: 12px 14px;
   }
 }
-
-@media (max-width: 768px) {
-  .workflow-step-manager-modal {
-    width: 100%;
-    max-width: 100%;
-    max-height: 100vh;
-    max-height: 100dvh;
-    border-radius: 0;
-  }
-}