fix(store-docs): readable blockquote in dark theme

flutter_markdown's MarkdownStyleSheet.fromTheme defaults the
blockquote background to a hardcoded Colors.blue.shade100. In
Dark Theme the text colour stays white-on-surface, so a
blockquote rendered '> Note: ...' shows as white text on
light blue — unreadable.

Override blockquoteDecoration to use theme tokens
(surfaceContainer + left primary accent border) and pin
blockquote text to onSurface. tableCellsDecoration gets the
same theme-driven treatment for the same class of issue.

Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

lib/pages/store.dart

@@ -2567,6 +2567,36 @@ class _DocsPanel extends StatelessWidget {
                 color: theme.colorScheme.surfaceContainer,
                 borderRadius: BorderRadius.circular(FaiRadius.sm),
               ),
+              // flutter_markdown default-blockquote nutzt
+              // hardcodiertes `Colors.blue.shade100` als
+              // Background, was im Dark-Theme mit weißem Text
+              // unlesbar wird. Wir setzen Theme-konsistente
+              // Werte: surfaceContainer-Background + linke
+              // Akzent-Border, Text in onSurface.
+              blockquote: theme.textTheme.bodyMedium?.copyWith(
+                color: theme.colorScheme.onSurface,
+              ),
+              blockquoteDecoration: BoxDecoration(
+                color: theme.colorScheme.surfaceContainer,
+                borderRadius: BorderRadius.circular(FaiRadius.sm),
+                border: Border(
+                  left: BorderSide(
+                    color: theme.colorScheme.primary,
+                    width: 3,
+                  ),
+                ),
+              ),
+              blockquotePadding: const EdgeInsets.fromLTRB(
+                FaiSpace.md,
+                FaiSpace.sm,
+                FaiSpace.sm,
+                FaiSpace.sm,
+              ),
+              // Tabellen-Cells haben dasselbe Default-Problem
+              // (Material-2-Light-Annahme). Theme-Werte erzwingen.
+              tableCellsDecoration: BoxDecoration(
+                color: theme.colorScheme.surfaceContainerHigh,
+              ),
             ),
           ),
         );