fix: Ignore employment overlaps at the same company

Sequential roles at the same company (promotions, transfers) should not
be flagged as suspicious overlaps. Only flag overlaps between different
companies.

- Add IsSameCompany() check before flagging overlaps
- Normalize company names to handle variations like "BMW" vs "BMW UK"
- Remove common suffixes (Ltd, PLC, Group, etc.) for comparison

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

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

src/RealCV.Infrastructure/Services/TimelineAnalyserService.cs

@@ -120,6 +120,15 @@ public sealed class TimelineAnalyserService : ITimelineAnalyserService
                 var earlier = sortedEmployment[i];
                 var later = sortedEmployment[j];
 
+                // Skip overlaps at the same company (internal promotions/transfers)
+                if (IsSameCompany(earlier.CompanyName, later.CompanyName))
+                {
+                    _logger.LogDebug(
+                        "Ignoring overlap at same company: {Company1} -> {Company2}",
+                        earlier.CompanyName, later.CompanyName);
+                    continue;
+                }
+
                 var overlap = CalculateOverlap(earlier, later);
 
                 if (overlap is not null && overlap.Value.Months > AllowedOverlapMonths)
@@ -143,6 +152,59 @@ public sealed class TimelineAnalyserService : ITimelineAnalyserService
         return overlaps;
     }
 
+    /// <summary>
+    /// Determines if two company names refer to the same company.
+    /// Handles variations like "BMW" vs "BMW UK" vs "BMW Group".
+    /// </summary>
+    private static bool IsSameCompany(string? company1, string? company2)
+    {
+        if (string.IsNullOrWhiteSpace(company1) || string.IsNullOrWhiteSpace(company2))
+        {
+            return false;
+        }
+
+        // Normalize names for comparison
+        var name1 = NormalizeCompanyName(company1);
+        var name2 = NormalizeCompanyName(company2);
+
+        // Exact match after normalization
+        if (name1.Equals(name2, StringComparison.OrdinalIgnoreCase))
+        {
+            return true;
+        }
+
+        // Check if one contains the other (for "BMW" vs "BMW UK" cases)
+        if (name1.Length >= 3 && name2.Length >= 3)
+        {
+            if (name1.StartsWith(name2, StringComparison.OrdinalIgnoreCase) ||
+                name2.StartsWith(name1, StringComparison.OrdinalIgnoreCase))
+            {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    private static string NormalizeCompanyName(string name)
+    {
+        // Remove common suffixes and normalize
+        var normalized = name.Trim();
+
+        string[] suffixes = ["Ltd", "Ltd.", "Limited", "PLC", "Plc", "Inc", "Inc.",
+            "Corporation", "Corp", "Corp.", "UK", "Group", "(UK)", "& Co", "& Co."];
+
+        foreach (var suffix in suffixes)
+        {
+            if (normalized.EndsWith(" " + suffix, StringComparison.OrdinalIgnoreCase))
+            {
+                normalized = normalized[..^(suffix.Length + 1)].Trim();
+            }
+        }
+
+        return normalized;
+    }
+
     private static (DateOnly Start, DateOnly End, int Months)? CalculateOverlap(
         EmploymentEntry earlier,
         EmploymentEntry later)