Add debug logging to company matching for diagnosis

src/TrueCV.Infrastructure/Services/CompanyVerifierService.cs

@@ -570,7 +570,7 @@ public sealed class CompanyVerifierService : ICompanyVerifierService
         return matches?.Company;
     }
 
-    private static (CompaniesHouseSearchItem Item, int Score)? FindBestMatch(
+    private (CompaniesHouseSearchItem Item, int Score)? FindBestMatch(
         string companyName,
         List<CompaniesHouseSearchItem> items,
         DateOnly? claimedStartDate)
@@ -583,30 +583,46 @@ public sealed class CompanyVerifierService : ICompanyVerifierService
             .Where(m => m.Score >= FuzzyMatchThreshold)
             .ToList();
 
+        _logger.LogDebug("Found {Count} matches above threshold for '{CompanyName}'", matches.Count, companyName);
+        foreach (var m in matches.Take(5))
+        {
+            _logger.LogDebug("  Match: {Title} ({Number}), Score: {Score}, DateOfCreation: {Date}",
+                m.Item.Title, m.Item.CompanyNumber, m.Score, m.Item.DateOfCreation ?? "null");
+        }
+
         if (matches.Count == 0) return null;
 
         // If we have a claimed start date, prefer companies that existed at that time
         if (claimedStartDate.HasValue)
         {
+            _logger.LogDebug("Filtering for companies that existed at claimed start date: {StartDate}", claimedStartDate.Value);
+
             var existedAtStartDate = matches
                 .Where(m =>
                 {
                     var incDate = DateHelpers.ParseDate(m.Item.DateOfCreation);
-                    // Company existed if it was incorporated before the claimed start date
+                    var existed = incDate == null || incDate <= claimedStartDate.Value;
-                    return incDate == null || incDate <= claimedStartDate.Value;
+                    _logger.LogDebug("  {Title}: IncDate={IncDate}, Existed={Existed}",
+                        m.Item.Title, incDate?.ToString() ?? "null", existed);
+                    return existed;
                 })
                 .OrderByDescending(m => m.Score)
                 .ToList();
 
+            _logger.LogDebug("Companies that existed at start date: {Count}", existedAtStartDate.Count);
+
             // If any matches existed at the start date, prefer those
             if (existedAtStartDate.Count > 0)
             {
+                _logger.LogDebug("Selected: {Title} ({Number})", existedAtStartDate[0].Item.Title, existedAtStartDate[0].Item.CompanyNumber);
                 return existedAtStartDate[0];
             }
         }
 
         // Fall back to highest score if no temporal match
-        return matches.OrderByDescending(m => m.Score).First();
+        var fallback = matches.OrderByDescending(m => m.Score).First();
+        _logger.LogDebug("Falling back to highest score: {Title} ({Number})", fallback.Item.Title, fallback.Item.CompanyNumber);
+        return fallback;
     }
 
     private async Task CacheCompanyAsync(CompaniesHouseSearchItem item, CompaniesHouseCompany? details)