feat(data): rename *.Services projects, lift TrackEntity onto BlazorBlocks data layer, regenerate initial Postgres migration

DeepDrftWeb.Services → DeepDrftData; DeepDrftContent.Services → DeepDrftContent.Data.
TrackEntity:BaseEntity, TrackRepository:Repository<>, TrackManager:Manager<>+ITrackService.
Drops DeepDrftModels PagingParameters/PagedResult in favour of Models.Common.* from BlazorBlocks.
InitialCreate migration captures full schema including is_deleted index.

DeepDrftContent.Data/FileDatabase/Abstractions/IIndexFactory.cs

@@ -0,0 +1,51 @@
+using DeepDrftContent.Data.FileDatabase.Models;
+using IndexType = DeepDrftContent.Data.FileDatabase.Services.IndexType;
+
+namespace DeepDrftContent.Data.FileDatabase.Abstractions;
+
+/// <summary>
+/// Interface for creating index instances
+/// </summary>
+public interface IIndexFactory
+{
+    /// <summary>
+    /// Loads an existing index of the specified type
+    /// </summary>
+    Task<IIndex?> LoadIndexAsync(IndexType type, string rootPath);
+
+    /// <summary>
+    /// Creates a directory index
+    /// </summary>
+    Task<IDirectoryIndex?> CreateDirectoryIndexAsync(string rootPath);
+    
+    /// <summary>
+    /// Loads existing directory index or creates new one if loading fails
+    /// </summary>
+    Task<IDirectoryIndex?> LoadOrCreateDirectoryIndexAsync(string rootPath);
+    
+    /// <summary>
+    /// Creates a vault index with the specified vault type
+    /// </summary>
+    Task<IVaultIndex?> CreateVaultIndexAsync(string rootPath, MediaVaultType vaultType);
+    
+    /// <summary>
+    /// Loads existing vault index or creates new one with the specified vault type if loading fails
+    /// </summary>
+    Task<IVaultIndex?> LoadOrCreateVaultIndexAsync(string rootPath, MediaVaultType vaultType);
+}
+
+/// <summary>
+/// Interface for creating index data objects
+/// </summary>
+public interface IIndexDataFactory
+{
+    /// <summary>
+    /// Creates index data for serialization
+    /// </summary>
+    object CreateIndexData(IndexType type, IIndex index);
+
+    /// <summary>
+    /// Creates index instance from data
+    /// </summary>
+    IIndex CreateIndexFromData(IndexType type, object indexData);
+}