feat(models): implement typed response models for PVE 8.x and 9.x

Add C# model classes for all PVE API resources: nodes, VMs, VM config,
containers, storage, network interfaces, SDN zones/vnets, users, roles,
permissions, snapshots, tasks, and cluster status. All models use dual
JSON attributes (System.Text.Json + Newtonsoft.Json), nullable optional
fields, and human-readable ToString() overrides.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/PSProxmoxVE.Core/Models/Storage/PveStorage.cs

@@ -0,0 +1,89 @@
+using System.Text.Json.Serialization;
+using Newtonsoft.Json;
+
+namespace PSProxmoxVE.Core.Models.Storage;
+
+/// <summary>
+/// Represents a Proxmox VE storage entry as returned by the /storage or /nodes/{node}/storage endpoints.
+/// </summary>
+public class PveStorage
+{
+    /// <summary>
+    /// The unique identifier / name of the storage pool.
+    /// </summary>
+    [JsonPropertyName("storage")]
+    [JsonProperty("storage")]
+    public string Storage { get; set; } = string.Empty;
+
+    /// <summary>
+    /// The storage backend type (e.g., "dir", "lvm", "zfspool", "nfs", "cifs", "rbd").
+    /// </summary>
+    [JsonPropertyName("type")]
+    [JsonProperty("type")]
+    public string? Type { get; set; }
+
+    /// <summary>
+    /// Comma-separated list of content types this storage supports
+    /// (e.g., "images,rootdir,backup,snippets,iso,vztmpl").
+    /// </summary>
+    [JsonPropertyName("content")]
+    [JsonProperty("content")]
+    public string? Content { get; set; }
+
+    /// <summary>
+    /// Total capacity of the storage pool, in bytes.
+    /// </summary>
+    [JsonPropertyName("total")]
+    [JsonProperty("total")]
+    public long? Total { get; set; }
+
+    /// <summary>
+    /// Used capacity of the storage pool, in bytes.
+    /// </summary>
+    [JsonPropertyName("used")]
+    [JsonProperty("used")]
+    public long? Used { get; set; }
+
+    /// <summary>
+    /// Available (free) capacity of the storage pool, in bytes.
+    /// </summary>
+    [JsonPropertyName("avail")]
+    [JsonProperty("avail")]
+    public long? Available { get; set; }
+
+    /// <summary>
+    /// Indicates whether the storage is enabled (1) or disabled (0) in the configuration.
+    /// </summary>
+    [JsonPropertyName("enabled")]
+    [JsonProperty("enabled")]
+    public int? Enabled { get; set; }
+
+    /// <summary>
+    /// Indicates whether the storage is shared across all cluster nodes (1) or node-local (0).
+    /// </summary>
+    [JsonPropertyName("shared")]
+    [JsonProperty("shared")]
+    public int? Shared { get; set; }
+
+    /// <summary>
+    /// Indicates whether the storage is currently active and reachable (1) or not (0).
+    /// </summary>
+    [JsonPropertyName("active")]
+    [JsonProperty("active")]
+    public int? Active { get; set; }
+
+    /// <summary>The node this storage entry is associated with. Populated by cmdlets after retrieval.</summary>
+    public string? Node { get; set; }
+
+    /// <inheritdoc />
+    public override string ToString()
+    {
+        var usedGb = Used.HasValue ? $"{Used.Value / 1024.0 / 1024 / 1024:F1} GB" : "N/A";
+        var totalGb = Total.HasValue ? $"{Total.Value / 1024.0 / 1024 / 1024:F1} GB" : "N/A";
+        var availGb = Available.HasValue ? $"{Available.Value / 1024.0 / 1024 / 1024:F1} GB" : "N/A";
+        var activeStr = Active is 1 ? "active" : "inactive";
+        var sharedStr = Shared is 1 ? "shared" : "local";
+        return $"Storage: {Storage} | Type: {Type ?? "N/A"} | {activeStr} | {sharedStr} | "
+             + $"Used: {usedGb}/{totalGb} | Free: {availGb} | Content: {Content ?? "N/A"}";
+    }
+}

src/PSProxmoxVE.Core/Models/Storage/PveStorageContent.cs

@@ -0,0 +1,87 @@
+using System;
+using System.Text.Json.Serialization;
+using Newtonsoft.Json;
+
+namespace PSProxmoxVE.Core.Models.Storage;
+
+/// <summary>
+/// Represents a single content item (disk image, backup, ISO, template, etc.)
+/// stored within a Proxmox VE storage pool, as returned by
+/// the /nodes/{node}/storage/{storage}/content endpoint.
+/// </summary>
+public class PveStorageContent
+{
+    /// <summary>
+    /// The full volume identifier in the form "storage:volumename"
+    /// (e.g., "local-lvm:vm-100-disk-0").
+    /// </summary>
+    [JsonPropertyName("volid")]
+    [JsonProperty("volid")]
+    public string VolId { get; set; } = string.Empty;
+
+    /// <summary>
+    /// The content type of this volume (e.g., "images", "backup", "iso", "vztmpl", "rootdir").
+    /// </summary>
+    [JsonPropertyName("content")]
+    [JsonProperty("content")]
+    public string? Content { get; set; }
+
+    /// <summary>
+    /// The disk image format (e.g., "raw", "qcow2", "vmdk", "subvol").
+    /// </summary>
+    [JsonPropertyName("format")]
+    [JsonProperty("format")]
+    public string? Format { get; set; }
+
+    /// <summary>
+    /// The size of the volume in bytes.
+    /// </summary>
+    [JsonPropertyName("size")]
+    [JsonProperty("size")]
+    public long? Size { get; set; }
+
+    /// <summary>
+    /// Unix timestamp of when the volume was created.
+    /// </summary>
+    [JsonPropertyName("ctime")]
+    [JsonProperty("ctime")]
+    public long? CreationTime { get; set; }
+
+    /// <summary>
+    /// The VM or container ID that owns this volume, if applicable (e.g., for disk images and backups).
+    /// </summary>
+    [JsonPropertyName("vmid")]
+    [JsonProperty("vmid")]
+    public int? VmId { get; set; }
+
+    /// <summary>
+    /// Optional notes or description attached to the volume (commonly used on backup files).
+    /// </summary>
+    [JsonPropertyName("notes")]
+    [JsonProperty("notes")]
+    public string? Notes { get; set; }
+
+    /// <summary>
+    /// Verification status of the volume, if applicable (e.g., for backups verified with vzdump).
+    /// </summary>
+    [JsonPropertyName("verification")]
+    [JsonProperty("verification")]
+    public string? Verification { get; set; }
+
+    /// <summary>The storage identifier this content resides on. Populated by cmdlets after retrieval.</summary>
+    public string? Storage { get; set; }
+
+    /// <summary>The node this content was retrieved from. Populated by cmdlets after retrieval.</summary>
+    public string? Node { get; set; }
+
+    /// <inheritdoc />
+    public override string ToString()
+    {
+        var sizeGb = Size.HasValue ? $"{Size.Value / 1024.0 / 1024 / 1024:F2} GB" : "N/A";
+        var created = CreationTime.HasValue
+            ? DateTimeOffset.FromUnixTimeSeconds(CreationTime.Value).ToString("yyyy-MM-dd HH:mm:ss")
+            : "N/A";
+        return $"Volume: {VolId} | Content: {Content ?? "N/A"} | Format: {Format ?? "N/A"} | "
+             + $"Size: {sizeGb} | Created: {created}";
+    }
+}