refactor: restructure solution into -models/-data/-api project taxonomy

Phases 1-10 of the planned refactoring:

Phase 1: rename shared-models -> common
  - namespace Shared.Models -> Common throughout
  - remove stale AspNetCore.Http.Features 5.0 reference

Phase 2: create shared-data with abstract BaseEntity
  - BaseEntity: required string Id { get; init; } + DateTime CreatedAt { get; init; }

Phase 3: rename myai-models -> myai-data
  - namespace MyAi.Models -> MyAi.Data
  - MigrationsAssembly("myai-data")

Phase 4: rename cv-search-models -> cv-search-data
  - namespace CvSearch.Models -> CvSearch.Data
  - move JobSearchSettings to cv-matcher-api-models
  - JobSearch*Entity now inherits BaseEntity

Phase 5: extract rag-data from rag-api
  - new project: Apis/rag-data with RagDbContext + entities + migrations
  - RagDocumentEntity inherits BaseEntity; cache entities use CacheKey PK
  - fix duplicate AddHttpClient<RagAiClient>/AddScoped registrations in rag-api
  - MigrationsAssembly("rag-data")

Phase 6: extract cv-matcher-data from cv-matcher-api
  - new project: Apis/cv-matcher-data with CvMatcherDbContext + entities + migrations
  - CvMatchResultEntity inherits BaseEntity; CvMatcherChatCacheEntity uses CacheKey PK
  - MigrationsAssembly("cv-matcher-data")

Phase 7: create empty cv-cleanup-job-models and cv-search-job-models

Phase 8: update all 5 Dockerfiles for renamed/new projects

Phase 9: reorganise .sln virtual folders (Apis/Jobs/Models/Data/Helpers)
  - update root CLAUDE.md with new project taxonomy and migration commands
  - update cv-matcher-api/CLAUDE.md and cv-search-job/CLAUDE.md

Phase 10: add Directory.Packages.props for centralised NuGet versions
  - remove Version= from all PackageReference elements in active .csproj files

No database changes. No runtime behaviour changes.
All MigrationId strings in __EFMigrationsHistory are unaffected.

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

Apis/myai-data/Data/Entities/TemplateEntity.cs

@@ -0,0 +1,11 @@
+namespace MyAi.Data.Entities;
+
+// composite PK (Key + Language) — BaseEntity not applicable
+public sealed class TemplateEntity
+{
+    public string Key { get; set; } = string.Empty;
+    public string Language { get; set; } = string.Empty;
+    public string Value { get; set; } = string.Empty;
+    public string Description { get; set; } = string.Empty;
+    public DateTime UpdatedAt { get; set; }
+}

Apis/myai-data/Data/MyAiDbContext.cs

@@ -0,0 +1,30 @@
+using MyAi.Data.Entities;
+using Microsoft.EntityFrameworkCore;
+
+namespace MyAi.Data;
+
+public sealed class MyAiDbContext : DbContext
+{
+    public const string SchemaName = "myAi";
+    public const string MigrationTableName = "_MyAiMigrations";
+
+    public MyAiDbContext(DbContextOptions<MyAiDbContext> options) : base(options) { }
+
+    public DbSet<TemplateEntity> Templates => Set<TemplateEntity>();
+
+    protected override void OnModelCreating(ModelBuilder modelBuilder)
+    {
+        modelBuilder.HasDefaultSchema(SchemaName);
+
+        modelBuilder.Entity<TemplateEntity>(entity =>
+        {
+            entity.ToTable("Templates");
+            entity.HasKey(x => new { x.Key, x.Language });
+            entity.Property(x => x.Key).HasMaxLength(128);
+            entity.Property(x => x.Language).HasMaxLength(8);
+            entity.Property(x => x.Value).IsRequired();
+            entity.Property(x => x.Description).HasMaxLength(500).HasDefaultValue(string.Empty);
+            entity.Property(x => x.UpdatedAt).HasDefaultValueSql("SYSUTCDATETIME()");
+        });
+    }
+}