Clean up namespaces (#410)

No meaningful code changes, just lots of namespace shuffling to have fewer namespaces and to put things in better namespaces.

src/ModelContextProtocol/Protocol/Resource.cs

@@ -0,0 +1,78 @@
+using System.Text.Json.Serialization;
+
+namespace ModelContextProtocol.Protocol;
+
+/// <summary>
+/// Represents a known resource that the server is capable of reading.
+/// </summary>
+/// <remarks>
+/// See the <see href="https://github.com/modelcontextprotocol/specification/blob/main/schema/">schema</see> for details.
+/// </remarks>
+public record Resource
+{
+    /// <summary>
+    /// Gets or sets the URI of this resource.
+    /// </summary>
+    [JsonPropertyName("uri")]
+    public required string Uri { get; init; }
+
+    /// <summary>
+    /// Gets or sets a human-readable name for this resource.
+    /// </summary>
+    [JsonPropertyName("name")]
+    public required string Name { get; init; }
+
+    /// <summary>
+    /// Gets or sets a description of what this resource represents.
+    /// </summary>
+    /// <remarks>
+    /// <para>
+    /// This can be used by clients to improve the LLM's understanding of available resources. It can be thought of like a \"hint\" to the model.
+    /// </para>
+    /// <para>
+    /// The description should provide clear context about the resource's content, format, and purpose.
+    /// This helps AI models make better decisions about when to access or reference the resource.
+    /// </para>
+    /// <para>
+    /// Client applications can also use this description for display purposes in user interfaces
+    /// or to help users understand the available resources.
+    /// </para>
+    /// </remarks>
+    [JsonPropertyName("description")]
+    public string? Description { get; init; }
+
+    /// <summary>
+    /// Gets or sets the MIME type of this resource.
+    /// </summary>
+    /// <remarks>
+    /// <para>
+    /// <see cref="MimeType"/> specifies the format of the resource content, helping clients to properly interpret and display the data.
+    /// Common MIME types include "text/plain" for plain text, "application/pdf" for PDF documents,
+    /// "image/png" for PNG images, and "application/json" for JSON data.
+    /// </para>
+    /// <para>
+    /// This property may be <see langword="null"/> if the MIME type is unknown or not applicable for the resource.
+    /// </para>
+    /// </remarks>
+    [JsonPropertyName("mimeType")]
+    public string? MimeType { get; init; }
+
+    /// <summary>
+    /// Gets or sets the size of the raw resource content (before base64 encoding), in bytes, if known.
+    /// </summary>
+    /// <remarks>
+    /// This can be used by applications to display file sizes and estimate context window usage.
+    /// </remarks>
+    [JsonPropertyName("size")]
+    public long? Size { get; init; }
+
+    /// <summary>
+    /// Gets or sets optional annotations for the resource.
+    /// </summary>
+    /// <remarks>
+    /// These annotations can be used to specify the intended audience (<see cref="Role.User"/>, <see cref="Role.Assistant"/>, or both)
+    /// and the priority level of the resource. Clients can use this information to filter or prioritize resources for different roles.
+    /// </remarks>
+    [JsonPropertyName("annotations")]
+    public Annotations? Annotations { get; init; }
+}