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/rag-api/Program.cs

@@ -1,15 +1,15 @@
 using System.Reflection;
 using Api.Clients.Ai;
 using Api.Clients.Ai.Contracts;
-using Api.Data;
-using Api.Data.Repositories;
-using Api.Data.Repositories.Contracts;
+using Rag.Data;
+using Rag.Data.Repositories;
+using Rag.Data.Repositories.Contracts;
 using Api.Services;
 using Api.Services.Contracts;
 using Microsoft.EntityFrameworkCore;
 using Rag.Models.Settings;
 using Serilog;
-using Shared.Models.Settings;
+using Common.Settings;
 using StartupHelpers;
 
 StartupExtensions.LoadDotEnvFile();
@@ -39,11 +39,10 @@ try
         options.UseSqlServer(connectionString, sql =>
         {
             sql.MigrationsHistoryTable(RagDbContext.MigrationTableName, RagDbContext.SchemaName);
+            sql.MigrationsAssembly("rag-data");
         });
     });
 
-    builder.Services.AddHttpClient<RagAiClient>();
-    builder.Services.AddScoped<IRagRepository, EfRagRepository>();
     builder.Services.AddHttpClient<RagAiClient>();
     builder.Services.AddScoped<IRagRepository, EfRagRepository>();
     builder.Services.AddScoped<IAiClient, CachedRagAiClient>();