Respect UI language in match result — LLM responds in user's selected language

The frontend sends the active language code (currentLang()) with every match
request. CvMatcherService injects a language instruction into the system prompt
so the LLM returns summary, strengths, gaps, recommendations, and evidence in
the correct language. The match result cache (CvMatchResults) now includes
Language as part of the lookup key so Romanian and English results are stored
and retrieved independently. Existing cached rows default to 'en'.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Apis/cv-matcher-api/Data/Entities/CvMatchResultEntity.cs

@@ -5,6 +5,7 @@ public sealed class CvMatchResultEntity
     public string Id { get; set; } = string.Empty;
     public string CvDocumentId { get; set; } = string.Empty;
     public string JobDocumentId { get; set; } = string.Empty;
+    public string Language { get; set; } = "en";
     public string ResultJson { get; set; } = string.Empty;
     public int Score { get; set; }
     public DateTime CreatedAt { get; set; } = DateTime.UtcNow;