fix: restore v0.5.2 architecture + wire AudioAnalyser correctly

wire AudioAnalyser: prepareToPlay + processBlock + MCP callback (3 additions)

Upload Source/Plugin/PluginBridgeProcessor.cpp

fix: findHelperBinary looks for .app bundle, not bare executable

implement Helper test-load: spawns Helper before in-process load, blocks crashy plugins

Upload Source/Plugin/PluginBridgeProcessor.cpp

Fix: Add hidePluginGui() implementation

Fix: PluginBridgeProcessor.cpp use flat include for IPCProtocol.h (Source/Shared in include dirs)

Out-of-process rebuild: Add Plugin/PluginBridgeProcessor.cpp — routes audio through shared memory to helper