Add AI-powered company name matching using Claude API

Replace fuzzy string matching with semantic AI matching to fix false
positives where similar-sounding but different companies were matched
(e.g., "Families First CiC" incorrectly matching "FAMILIES AGAINST
CONFORMITY LTD").

Changes:
- Add ICompanyNameMatcherService interface and AICompanyNameMatcherService
  implementation using Claude Sonnet 4 for semantic company name comparison
- Add SemanticMatchResult and related models for AI match results
- Update CompanyVerifierService to use AI matching with fuzzy fallback
- Add detection for public sector employers, charities, and self-employed
  entries that cannot be verified via Companies House
- Update tests to work with new AI matcher integration

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

src/TrueCV.Infrastructure/DependencyInjection.cs

@@ -90,6 +90,7 @@ public static class DependencyInjection
 
         // Register services
         services.AddScoped<ICVParserService, CVParserService>();
+        services.AddScoped<ICompanyNameMatcherService, AICompanyNameMatcherService>();
         services.AddScoped<ICompanyVerifierService, CompanyVerifierService>();
         services.AddScoped<IEducationVerifierService, EducationVerifierService>();
         services.AddScoped<ITimelineAnalyserService, TimelineAnalyserService>();