Only allow post-level spoiler text for Friendica servers with v2023.03 or later

lib/screens/editor.dart

@@ -178,6 +178,8 @@ class _EditorScreenState extends State<EditorScreen> {
 
     final vc = getIt<FriendicaVersionChecker>();
     final canEdit = vc.canUseFeature(RelaticaFeatures.statusEditing);
+    final canSpoilerText = vc.canUseFeature(RelaticaFeatures.postSpoilerText) ||
+        widget.parentId.isNotEmpty;
 
     late final body;
 
@@ -205,14 +207,14 @@ class _EditorScreenState extends State<EditorScreen> {
                   buildCommentPreview(context, parentEntry!),
                 TextFormField(
                   readOnly: isSubmitting,
-                  enabled: !isSubmitting,
+                  enabled: !isSubmitting && canSpoilerText,
                   controller: spoilerController,
                   decoration: InputDecoration(
-                    labelText: '$statusType Spoiler Text (optional)',
+                    labelText: canSpoilerText
+                        ? '$statusType Spoiler Text (optional)'
+                        : 'Your server doesnt support $statusType Spoiler Text',
                     border: OutlineInputBorder(
-                      borderSide: BorderSide(
-                        color: Theme.of(context).backgroundColor,
-                      ),
+                      borderSide: const BorderSide(),
                       borderRadius: BorderRadius.circular(5.0),
                     ),
                   ),
@@ -290,9 +292,7 @@ class _EditorScreenState extends State<EditorScreen> {
           labelText: '$statusType Content',
           alignLabelWithHint: true,
           border: OutlineInputBorder(
-            borderSide: BorderSide(
-              color: Theme.of(context).backgroundColor,
-            ),
+            borderSide: const BorderSide(),
             borderRadius: BorderRadius.circular(5.0),
           ),
         ),

lib/services/feature_version_checker.dart

@@ -6,6 +6,7 @@ import '../globals.dart';
 import '../models/friendica_version.dart';
 
 enum RelaticaFeatures {
+  postSpoilerText,
   statusEditing,
 }
 
@@ -43,6 +44,7 @@ class FriendicaVersionChecker {
       "This account's server doesn't meet the necessary minimum requirement: ${getVersionRequirement(feature).toVersionString()}";
 
   static final featureVersionRequirement = <RelaticaFeatures, FriendicaVersion>{
+    RelaticaFeatures.postSpoilerText: v2023_03,
     RelaticaFeatures.statusEditing: v2023_03,
   };
 }