feat(ui): add universal data export (CSV, JSON, Markdown, SQL dump) to ResultsTab

lib/features/main_screen/results_tab.dart

@@ -1,12 +1,8 @@
 import 'dart:async' show unawaited;
 
 import 'package:flutter/material.dart' as material;
-import 'package:flutter/services.dart' show Clipboard, ClipboardData;
-import 'package:querya_desktop/core/csv/result_grid_csv.dart';
-import 'package:querya_desktop/core/csv/save_result_grid_csv.dart';
-import 'package:querya_desktop/core/json/result_grid_json.dart';
-import 'package:querya_desktop/core/json/save_result_grid_json.dart';
 import 'package:querya_desktop/features/main_screen/result_grid_view.dart';
+import 'package:querya_desktop/shared/services/data_export_service.dart';
 import 'package:querya_desktop/shared/widgets/widgets.dart';
 
 /// Query output: grid, loading, error, or placeholder.
@@ -84,67 +80,67 @@ class ResultsTab extends StatelessWidget {
                   size: ButtonSize.small,
                   onPressed: () {
                     unawaited(() async {
-                      final outcome = await saveResultGridCsvFile(
+                      await DataExportService.copyToClipboard(
+                        DataExportFormat.csv,
                         columns: columns,
                         rows: rows,
                       );
-                      if (!context.mounted) return;
-                      if (outcome == SaveResultGridCsvOutcome.error) {
-                        await _showSaveFileErrorDialog(context);
-                      }
                     }());
                   },
                   leading: const material.Icon(
-                    material.Icons.save_alt_rounded,
+                    material.Icons.copy_rounded,
                     size: 14,
                   ),
-                  child: const Text('Save as CSV…'),
+                  child: const Text('Copy as CSV'),
                 ),
                 OutlineButton(
                   size: ButtonSize.small,
                   onPressed: () {
                     unawaited(() async {
-                      final outcome = await saveResultGridJsonFile(
+                      await DataExportService.copyToClipboard(
+                        DataExportFormat.json,
                         columns: columns,
                         rows: rows,
                       );
-                      if (!context.mounted) return;
-                      if (outcome == SaveResultGridJsonOutcome.error) {
-                        await _showSaveFileErrorDialog(context);
-                      }
                     }());
                   },
                   leading: const material.Icon(
-                    material.Icons.data_object_rounded,
+                    material.Icons.copy_rounded,
                     size: 14,
                   ),
-                  child: const Text('Save as JSON…'),
+                  child: const Text('Copy as JSON'),
                 ),
-                OutlineButton(
-                  size: ButtonSize.small,
-                  onPressed: () {
+                _ExportMenuButton(
+                  label: 'Copy formatted ▾',
+                  icon: material.Icons.copy_all_rounded,
+                  isSave: false,
+                  onSelected: (format) {
                     unawaited(() async {
-                      final csv = await resultGridAsCsvAsync(columns, rows);
-                      await Clipboard.setData(ClipboardData(text: csv));
+                      await DataExportService.copyToClipboard(
+                        format,
+                        columns: columns,
+                        rows: rows,
+                      );
                     }());
                   },
-                  leading: const material.Icon(
-                    material.Icons.copy_rounded,
-                    size: 14,
-                  ),
-                  child: const Text('Copy as CSV'),
                 ),
-                OutlineButton(
-                  size: ButtonSize.small,
-                  onPressed: () {
-                    final json = resultGridAsJson(columns, rows);
-                    Clipboard.setData(ClipboardData(text: json));
+                _ExportMenuButton(
+                  label: 'Save to file ▾',
+                  icon: material.Icons.save_alt_rounded,
+                  isSave: true,
+                  onSelected: (format) {
+                    unawaited(() async {
+                      final outcome = await DataExportService.saveToFile(
+                        format,
+                        columns: columns,
+                        rows: rows,
+                      );
+                      if (!context.mounted) return;
+                      if (outcome == SaveExportOutcome.error) {
+                        await _showSaveFileErrorDialog(context);
+                      }
+                    }());
                   },
-                  leading: const material.Icon(
-                    material.Icons.copy_rounded,
-                    size: 14,
-                  ),
-                  child: const Text('Copy as JSON'),
                 ),
               ],
             ),
@@ -175,3 +171,88 @@ Future<void> _showSaveFileErrorDialog(material.BuildContext context) {
     ),
   );
 }
+
+class _ExportMenuButton extends StatelessWidget {
+  const _ExportMenuButton({
+    required this.label,
+    required this.icon,
+    required this.onSelected,
+    required this.isSave,
+  });
+
+  final String label;
+  final material.IconData icon;
+  final material.ValueChanged<DataExportFormat> onSelected;
+  final bool isSave;
+
+  @override
+  Widget build(BuildContext context) {
+    return material.PopupMenuButton<DataExportFormat>(
+      tooltip: label,
+      onSelected: onSelected,
+      itemBuilder: (context) => [
+        material.PopupMenuItem(
+          value: DataExportFormat.csv,
+          child: material.Row(
+            children: [
+              const material.Icon(
+                  material.Icons.table_chart_outlined, size: 16),
+              const material.SizedBox(width: 8),
+              material.Text(isSave ? 'CSV (.csv)' : 'Copy as CSV'),
+            ],
+          ),
+        ),
+        material.PopupMenuItem(
+          value: DataExportFormat.json,
+          child: material.Row(
+            children: [
+              const material.Icon(
+                  material.Icons.data_object_rounded, size: 16),
+              const material.SizedBox(width: 8),
+              material.Text(isSave ? 'JSON (.json)' : 'Copy as JSON'),
+            ],
+          ),
+        ),
+        material.PopupMenuItem(
+          value: DataExportFormat.markdown,
+          child: material.Row(
+            children: [
+              const material.Icon(material.Icons.code_rounded, size: 16),
+              const material.SizedBox(width: 8),
+              material.Text(isSave ? 'Markdown Table (.md)' : 'Copy as Markdown Table'),
+            ],
+          ),
+        ),
+        material.PopupMenuItem(
+          value: DataExportFormat.sqlDump,
+          child: material.Row(
+            children: [
+              const material.Icon(material.Icons.storage_rounded, size: 16),
+              const material.SizedBox(width: 8),
+              material.Text(isSave ? 'SQL INSERT Dump (.sql)' : 'Copy as SQL Dump'),
+            ],
+          ),
+        ),
+      ],
+      child: material.Container(
+        padding: const material.EdgeInsets.symmetric(
+            horizontal: 10, vertical: 6),
+        decoration: material.BoxDecoration(
+          border: material.Border.all(
+            color: Theme.of(context).colorScheme.border,
+          ),
+          borderRadius: material.BorderRadius.circular(6),
+        ),
+        child: material.Row(
+          mainAxisSize: material.MainAxisSize.min,
+          children: [
+            material.Icon(icon,
+                size: 14, color: Theme.of(context).colorScheme.foreground),
+            const material.SizedBox(width: 6),
+            Text(label).small(),
+          ],
+        ),
+      ),
+    );
+  }
+}