Sprint 1: Add stub files — HostedPluginManager and AudioAnalyser (Phase 2)

Source/HostedPluginManager.h

@@ -0,0 +1,13 @@
+#pragma once
+
+// Phase 2 stub — will be implemented in Sprint 2
+// Manages loading/unloading of a hosted VST3/AU plugin inside PluginBridge
+
+class HostedPluginManager
+{
+public:
+    HostedPluginManager() = default;
+    ~HostedPluginManager() = default;
+
+    bool isLoaded() const { return false; }
+};