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/Services/MediaVaultFactory.cs

@@ -0,0 +1,19 @@
+using DeepDrftContent.Data.FileDatabase.Models;
+
+namespace DeepDrftContent.Data.FileDatabase.Services;
+
+/// <summary>
+/// Factory for creating media vaults
+/// </summary>
+public static class MediaVaultFactory
+{
+    public static async Task<MediaVault?> From(string rootPath, MediaVaultType mediaType, IndexFactoryService? factoryService = null)
+    {
+        return mediaType switch
+        {
+            MediaVaultType.Image => await ImageVault.FromAsync(rootPath, factoryService),
+            MediaVaultType.Audio => await AudioVault.FromAsync(rootPath, factoryService),
+            _ => null
+        };
+    }
+}