feat(cv-matcher): add AiPrompts table; remove MyAiDbContext dependency

cv-matcher-data:
- Add AiPromptEntity (Key, Language, Value, Description, UpdatedAt)
- Add AiPrompts DbSet to CvMatcherDbContext with composite PK
- Migration AddAiPrompts: create cvMatcher.AiPrompts table and seed
  ai.cv-match.system-prompt (language "*") with the current prompt value

cv-matcher-api:
- Add IAiPromptsRepository / EfAiPromptsRepository under Data/Repositories/
- CvMatcherService: inject IAiPromptsRepository; replace _templates.Render(...)
  with async DB lookup + simple string replacement
- Program.cs: register IAiPromptsRepository (scoped); remove MyAiDbContext,
  ITemplateService/DbTemplateService registrations and MyAiDbContext migration call
- Remove myai-data ProjectReference

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

Apis/cv-matcher-data/Migrations/CvMatcherDbContextModelSnapshot.cs

@@ -23,6 +23,37 @@ namespace CvMatcher.Data.Migrations
 
             SqlServerModelBuilderExtensions.UseIdentityColumns(modelBuilder);
 
+            modelBuilder.Entity("CvMatcher.Data.Entities.AiPromptEntity", b =>
+                {
+                    b.Property<string>("Key")
+                        .HasMaxLength(128)
+                        .HasColumnType("nvarchar(128)");
+
+                    b.Property<string>("Language")
+                        .HasMaxLength(8)
+                        .HasColumnType("nvarchar(8)");
+
+                    b.Property<string>("Description")
+                        .IsRequired()
+                        .ValueGeneratedOnAdd()
+                        .HasMaxLength(500)
+                        .HasColumnType("nvarchar(500)")
+                        .HasDefaultValue("");
+
+                    b.Property<DateTime>("UpdatedAt")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("datetime2")
+                        .HasDefaultValueSql("SYSUTCDATETIME()");
+
+                    b.Property<string>("Value")
+                        .IsRequired()
+                        .HasColumnType("nvarchar(max)");
+
+                    b.HasKey("Key", "Language");
+
+                    b.ToTable("AiPrompts", "cvMatcher");
+                });
+
             modelBuilder.Entity("CvMatcher.Data.Entities.CvMatchResultEntity", b =>
                 {
                     b.Property<string>("Id")