Backfill memo on re-sync and fix transactions table name in migration

Update duplicate handling during bank sync to populate the memo field
on existing transactions when it's empty. Fix raw SQL table name from
quoted "Transactions" to lowercase "transactions" matching the actual
PostgreSQL schema.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/Purrse.Api/Program.cs

@@ -131,7 +131,7 @@ using (var scope = app.Services.CreateScope())
     if (!applied)
     {
         var count = await db.Database.ExecuteSqlRawAsync(
-            "UPDATE \"Transactions\" SET \"Status\" = 1 WHERE \"FitId\" IS NOT NULL AND \"Status\" = 0");
+            "UPDATE transactions SET \"Status\" = 1 WHERE \"FitId\" IS NOT NULL AND \"Status\" = 0");
         if (count > 0)
             app.Services.GetRequiredService<ILogger<Program>>().LogInformation("Marked {Count} bank-synced transactions as Cleared", count);
         await db.Database.ExecuteSqlRawAsync(

src/Purrse.Api/Services/BankSyncService.cs

@@ -462,6 +462,16 @@ public class BankSyncService : IBankSyncService
 
                     if (duplicate != null)
                     {
+                        // Update memo if the existing transaction has no memo
+                        if (!string.IsNullOrEmpty(parsed.Memo))
+                        {
+                            var existing = await _db.Transactions.FindAsync(duplicate.ExistingTransactionId);
+                            if (existing != null && string.IsNullOrEmpty(existing.Memo))
+                            {
+                                existing.Memo = parsed.Memo;
+                            }
+                        }
+
                         skipped++;
                         continue;
                     }