fix: isolate payment amount evidence

frontend/lib/shared/services/recognition_diagnostic_formatter.dart

@@ -80,7 +80,10 @@ class RecognitionDiagnosticDisplay {
       'direction_unknown' => '识别到完成状态，但无法确认收支方向',
       'missing_amount' => '成功状态已识别，但没有找到金额',
       'expected_amount_missing' => '结果页没有金额，且付款前金额不唯一或未捕获',
-      'expected_amount_fallback' => '结果页金额缺失，已使用付款前确认的唯一金额',
+      'expected_amount_fallback' => '结果页未读到金额，已使用本次付款流程确认的金额',
+      'weak_expected_fallback' => '结果页未读到金额，付款前金额来源不可靠，请确认后入账',
+      'result_amount_conflict' => '结果页金额与本次付款金额不一致，请确认后入账',
+      'amount_source_untrusted' => '金额无法与当前付款流程可靠关联，请确认后入账',
       'red_packet_not_settled' => '红包尚未明确到账或退回，不会自动入账',
       'duplicate_result_surface' => '同一结果页已处理，本次刷新已忽略',
       'weak_status_confirm' => '只识别到弱完成状态，组合证据不足，需确认后入账',
@@ -123,7 +126,7 @@ class RecognitionDiagnosticDisplay {
 
   static String? _amountSourceLabel(String? value) {
     return switch (value) {
-      'expected' => '使用付款前金额',
+      'expected' => '使用本次付款金额',
       'result' => '使用结果页金额',
       _ => null,
     };
@@ -172,5 +175,8 @@ class RecognitionDiagnosticDisplay {
     'red_packet_not_settled',
     'weak_status_confirm',
     'ambiguous_or_unarmed',
+    'weak_expected_fallback',
+    'result_amount_conflict',
+    'amount_source_untrusted',
   };
 }