Add plugin isolation IPC scaffolding and host phase one docs (#5)

LanMountainDesktop.PluginSdk/IPluginWorkerContext.cs

@@ -0,0 +1,26 @@
+using LanMountainDesktop.PluginIsolation.Contracts;
+
+namespace LanMountainDesktop.PluginSdk;
+
+public interface IPluginWorkerContext
+{
+    string PluginId { get; }
+
+    PluginManifest Manifest { get; }
+
+    PluginRuntimeMode RuntimeMode { get; }
+
+    string SessionId { get; }
+
+    string HostPipeName { get; }
+
+    string ProtocolVersion { get; }
+
+    string PluginDirectory { get; }
+
+    string DataDirectory { get; }
+
+    IReadOnlyList<PluginCapabilityDeclaration> GrantedCapabilities { get; }
+
+    IReadOnlyDictionary<string, string> StartupProperties { get; }
+}