Add PocketBase client with contracts and sharp build tooling

Elternbeirat.PocketBase/RecordList.cs

@@ -0,0 +1,15 @@
+using System.Text.Json.Serialization;
+
+namespace Elternbeirat.PocketBase;
+
+/// <summary>
+/// The envelope PocketBase wraps a records list response in. Only <see cref="Items"/>
+/// is used; the paging fields are ignored because content volumes are small and the
+/// client requests a large page size in a single call.
+/// </summary>
+/// <typeparam name="T">The record type inside <c>items</c>.</typeparam>
+internal sealed record RecordList<T>
+{
+    [JsonPropertyName("items")]
+    public IReadOnlyList<T> Items { get; init; } = [];
+}