Prefer main trading companies over subsidiaries in company matching

When matching brand names like "ASDA", prefer the main employer company
(ASDA STORES LIMITED) over subsidiaries (ASDA DELIVERY LIMITED).

- Add SubsidiaryIndicators set (delivery, distribution, holdings, property, etc.)
- Add MainCompanyIndicators set (stores, retail, manufacturing, etc.)
- Add CalculateCompanyPriorityScore() method for ranking matches
- Sort matches by priority score first, then by fuzzy score
- Subsidiaries get -10 priority unless explicitly searched for
- Main trading companies get +5 priority, PLCs get +3

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/TrueCV.Infrastructure/Services/CompanyVerifierService.cs

@@ -45,6 +45,32 @@ public sealed class CompanyVerifierService : ICompanyVerifierService
         "68100", // Buying and selling of own real estate (often shell)
     };
 
+    // Words that indicate a subsidiary rather than the main trading company
+    // When someone says they worked for "ASDA", they likely mean ASDA STORES LIMITED,
+    // not ASDA DELIVERY LIMITED or ASDA PROPERTY HOLDINGS LIMITED
+    private static readonly HashSet<string> SubsidiaryIndicators = new(StringComparer.OrdinalIgnoreCase)
+    {
+        // Logistics/Operations subsidiaries
+        "delivery", "distribution", "logistics", "transport", "fleet", "haulage", "warehousing", "fulfilment",
+        // Property subsidiaries
+        "property", "properties", "estates", "land", "real estate", "developments",
+        // Financial/Holding subsidiaries
+        "holdings", "holding", "investments", "capital", "finance", "financial", "treasury",
+        // Administrative subsidiaries
+        "nominees", "nominee", "trustees", "trustee", "secretarial", "registrars",
+        // Insurance subsidiaries
+        "insurance", "assurance", "underwriting",
+        // Specific function subsidiaries
+        "leasing", "rentals", "procurement", "sourcing"
+    };
+
+    // Words that indicate a main trading/employer company (prefer these)
+    private static readonly HashSet<string> MainCompanyIndicators = new(StringComparer.OrdinalIgnoreCase)
+    {
+        "stores", "retail", "supermarkets", "superstores", "hypermarkets",
+        "manufacturing", "operations", "trading"
+    };
+
     // SIC codes for tech/software companies
     private static readonly HashSet<string> TechSicCodes = new()
     {
@@ -657,9 +683,15 @@ public sealed class CompanyVerifierService : ICompanyVerifierService
             .Select(item =>
             {
                 var itemTitle = item.Title.ToUpperInvariant();
+                var itemTitleLower = item.Title.ToLowerInvariant();
                 var scoreVsOriginal = Fuzz.TokenSetRatio(normalizedOriginal, itemTitle);
                 var scoreVsQuery = Fuzz.TokenSetRatio(normalizedQuery, itemTitle);
-                return (Item: item, Score: Math.Max(scoreVsOriginal, scoreVsQuery));
+                var baseScore = Math.Max(scoreVsOriginal, scoreVsQuery);
+
+                // Calculate priority adjustment for main company vs subsidiary
+                var priorityScore = CalculateCompanyPriorityScore(itemTitleLower, originalLower, queryLower);
+
+                return (Item: item, Score: baseScore, PriorityScore: priorityScore);
             })
             .Where(m => m.Score >= FuzzyMatchThreshold)
             .ToList();
@@ -667,8 +699,8 @@ public sealed class CompanyVerifierService : ICompanyVerifierService
         _logger.LogDebug("Found {Count} matches above threshold for '{CompanyName}' (query: '{Query}')", matches.Count, companyName, searchQuery);
         foreach (var m in matches.Take(5))
         {
-            _logger.LogDebug("  Match: {Title} ({Number}), Score: {Score}, DateOfCreation: {Date}",
+            _logger.LogDebug("  Match: {Title} ({Number}), Score: {Score}, Priority: {Priority}, DateOfCreation: {Date}",
-                m.Item.Title, m.Item.CompanyNumber, m.Score, m.Item.DateOfCreation ?? "null");
+                m.Item.Title, m.Item.CompanyNumber, m.Score, m.PriorityScore, m.Item.DateOfCreation ?? "null");
         }
 
         if (matches.Count == 0) return null;
@@ -687,7 +719,9 @@ public sealed class CompanyVerifierService : ICompanyVerifierService
                         m.Item.Title, incDate?.ToString() ?? "null", existed);
                     return existed;
                 })
-                .OrderByDescending(m => m.Score)
+                // Sort by priority first, then by fuzzy score
+                .OrderByDescending(m => m.PriorityScore)
+                .ThenByDescending(m => m.Score)
                 .ToList();
 
             _logger.LogDebug("Companies that existed at start date: {Count}", existedAtStartDate.Count);
@@ -695,8 +729,9 @@ public sealed class CompanyVerifierService : ICompanyVerifierService
             // 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);
+                var selected = existedAtStartDate[0];
-                return existedAtStartDate[0];
+                _logger.LogDebug("Selected: {Title} ({Number}), Priority: {Priority}", selected.Item.Title, selected.Item.CompanyNumber, selected.PriorityScore);
+                return (selected.Item, selected.Score);
             }
 
             // No companies existed at the claimed start date - don't match a wrong company
@@ -704,10 +739,59 @@ public sealed class CompanyVerifierService : ICompanyVerifierService
             return null;
         }
 
-        // No start date provided - just use highest score
+        // No start date provided - sort by priority then score
-        var fallback = matches.OrderByDescending(m => m.Score).First();
+        var fallback = matches
-        _logger.LogDebug("No start date filter, using highest score: {Title} ({Number})", fallback.Item.Title, fallback.Item.CompanyNumber);
+            .OrderByDescending(m => m.PriorityScore)
-        return fallback;
+            .ThenByDescending(m => m.Score)
+            .First();
+        _logger.LogDebug("No start date filter, using highest priority: {Title} ({Number}), Priority: {Priority}", fallback.Item.Title, fallback.Item.CompanyNumber, fallback.PriorityScore);
+        return (fallback.Item, fallback.Score);
+    }
+
+    /// <summary>
+    /// Calculates a priority score for company matching.
+    /// Higher scores = more likely to be the main employer company.
+    /// Penalizes subsidiaries (delivery, property, holdings, etc.) unless explicitly searched for.
+    /// Boosts main trading companies (stores, retail, etc.).
+    /// </summary>
+    private static int CalculateCompanyPriorityScore(string itemTitleLower, string originalLower, string queryLower)
+    {
+        var score = 0;
+
+        // Check if search explicitly mentions subsidiary indicators
+        var searchText = originalLower + " " + queryLower;
+
+        // Penalize subsidiary indicators (unless search explicitly included them)
+        foreach (var indicator in SubsidiaryIndicators)
+        {
+            if (itemTitleLower.Contains(indicator))
+            {
+                // Only penalize if the search didn't explicitly include this indicator
+                if (!searchText.Contains(indicator))
+                {
+                    score -= 10; // Significant penalty for subsidiaries
+                }
+                break; // Only apply one subsidiary penalty
+            }
+        }
+
+        // Boost main company indicators
+        foreach (var indicator in MainCompanyIndicators)
+        {
+            if (itemTitleLower.Contains(indicator))
+            {
+                score += 5; // Boost for main trading companies
+                break; // Only apply one boost
+            }
+        }
+
+        // Slight boost for PLC (usually the parent/main company)
+        if (itemTitleLower.EndsWith(" plc"))
+        {
+            score += 3;
+        }
+
+        return score;
     }
 
     private async Task CacheCompanyAsync(CompaniesHouseSearchItem item, CompaniesHouseCompany? details)