Fix merchant filtering in receipt mapping to be non-exclusive

Changed merchant filtering from exclusionary to relevance-based sorting.
This fixes the issue where transactions don't appear if the merchant
name doesn't exactly match.

Changes:
- Date range (±3 days) remains the primary hard filter
- Merchant name now sorts results by relevance instead of excluding
- Retrieves 100 candidates, sorts by match quality, returns top 50
- Case-insensitive matching using ToLower()

Relevance Scoring:
- Score 3: Exact match on merchant or transaction name
- Score 2: Partial match on merchant name (Contains)
- Score 1: Partial match on transaction name (Contains)
- Score 0: No match (still included if within date range)

Results sorted by: Match score → Date → ID

Benefits:
- McDonald's receipt will show all transactions in date range
- Best matches appear at top
- No transactions excluded due to name variations
- More forgiving for typos, abbreviations, etc.
- User can still see and select any transaction in date window

Example: Receipt says "McDonald's" but transaction says "MCDONALD'S #1234"
- Before: Excluded (no exact Contains match)
- After: Included, sorted to top (partial match score 2)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

MoneyMap/Pages/Receipts.cshtml.cs

@@ -232,7 +232,7 @@ namespace MoneyMap.Pages
                 .Where(t => !transactionsWithReceipts.Contains(t.Id))
                 .AsQueryable();
 
-            // If receipt has a date, filter by +/- 3 days
+            // If receipt has a date, filter by +/- 3 days (this is the primary filter)
             if (receipt.ReceiptDate.HasValue)
             {
                 var minDate = receipt.ReceiptDate.Value.AddDays(-3);
@@ -240,20 +240,50 @@ namespace MoneyMap.Pages
                 query = query.Where(t => t.Date >= minDate && t.Date <= maxDate);
             }
 
-            // If receipt has merchant, filter by merchant name
-            if (!string.IsNullOrWhiteSpace(receipt.Merchant))
-            {
-                query = query.Where(t =>
-                    (t.Merchant != null && t.Merchant.Name.Contains(receipt.Merchant)) ||
-                    t.Name.Contains(receipt.Merchant));
-            }
-
+            // Get all candidates within date range (don't filter by merchant in query)
             var candidates = await query
                 .OrderByDescending(t => t.Date)
                 .ThenByDescending(t => t.Id)
-                .Take(50) // Limit to 50 matches
+                .Take(100) // Get more candidates for sorting
                 .ToListAsync();
 
+            // If receipt has merchant, sort matches by relevance (but don't exclude)
+            if (!string.IsNullOrWhiteSpace(receipt.Merchant))
+            {
+                var merchantLower = receipt.Merchant.ToLower();
+
+                // Sort: exact matches first, then partial matches, then others
+                candidates = candidates
+                    .OrderByDescending(t =>
+                    {
+                        var merchantName = t.Merchant?.Name?.ToLower() ?? "";
+                        var transactionName = t.Name?.ToLower() ?? "";
+
+                        // Exact match on merchant or transaction name
+                        if (merchantName == merchantLower || transactionName == merchantLower)
+                            return 3;
+
+                        // Contains match on merchant
+                        if (merchantName.Contains(merchantLower))
+                            return 2;
+
+                        // Contains match on transaction name
+                        if (transactionName.Contains(merchantLower))
+                            return 1;
+
+                        // No match
+                        return 0;
+                    })
+                    .ThenByDescending(t => t.Date)
+                    .Take(50)
+                    .ToList();
+            }
+            else
+            {
+                // No merchant filter, just take top 50 by date
+                candidates = candidates.Take(50).ToList();
+            }
+
             // Calculate match scores and mark close amount matches
             var options = candidates.Select(t =>
             {