feat: implement matchedVia tracking for receipt items and enhance user alias management

flutter/lib/features/import/presentation/receipt_import_tab.dart

@@ -540,15 +540,16 @@ class _ReceiptImportTabState extends ConsumerState<ReceiptImportTab> {
         }
 
         final normalizedReceiptName = item.rawName.trim().toLowerCase();
-        final shouldLearnAlias =
-            canManageAliases &&
-            normalizedReceiptName.isNotEmpty &&
-            item.matchedProductId != pid;
+        // Spara alias för alla användare (user-scope) när raden inte redan matchades via alias,
+        // eller admin sparar global alias.
+        final alreadyAliasMatch = item.matchedVia == 'alias' && item.matchedProductId == pid;
+        final shouldLearnAlias = normalizedReceiptName.isNotEmpty && !alreadyAliasMatch;
         if (shouldLearnAlias) {
           try {
             await adminRepo.upsertReceiptAlias(
               receiptName: normalizedReceiptName,
               productId: pid,
+              isGlobal: canManageAliases,
             );
             aliasesLearned++;
           } catch (e, st) {
@@ -644,6 +645,31 @@ class _ReceiptImportTabState extends ConsumerState<ReceiptImportTab> {
     );
   }
 
+  Widget _buildMatchedViaBadge(ParsedReceiptItem item, ThemeData theme) {
+    final via = item.matchedVia;
+    if (via == null || via == 'none') return const SizedBox.shrink();
+
+    final (label, bg, fg) = switch (via) {
+      'alias' => ('Alias', Colors.teal.shade50, Colors.teal.shade800),
+      'wordmatch' => ('Ordmatch', Colors.blue.shade50, Colors.blue.shade800),
+      'ai' => ('AI-kategori', Colors.purple.shade50, Colors.purple.shade800),
+      _ => ('Matchad', theme.colorScheme.surfaceContainerHighest, theme.colorScheme.onSurfaceVariant),
+    };
+
+    return Container(
+      padding: const EdgeInsets.symmetric(horizontal: 7, vertical: 2),
+      decoration: BoxDecoration(
+        color: bg,
+        borderRadius: BorderRadius.circular(999),
+        border: Border.all(color: fg.withOpacity(0.3)),
+      ),
+      child: Text(
+        label,
+        style: theme.textTheme.labelSmall?.copyWith(color: fg, fontWeight: FontWeight.w600),
+      ),
+    );
+  }
+
   @override
   Widget build(BuildContext context) {
     final session = ref.watch(receiptImportSessionProvider);
@@ -797,6 +823,7 @@ class _ReceiptImportTabState extends ConsumerState<ReceiptImportTab> {
                                 fontWeight: FontWeight.w500,
                               ),
                             ),
+                            _buildMatchedViaBadge(item, theme),
                             if (edit.categorySource != null)
                               Container(
                                 padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 2),