refactor: reorganize project structure with modern C++ namespace organization

- Restructure include/ and src/ directories with logical grouping
- Move core components to spore/core/ (NodeContext, NetworkManager, TaskManager, ClusterManager, ApiServer)
- Move services to spore/services/ (NodeService, NetworkService, ClusterService, TaskService)
- Move types to spore/types/ (NodeInfo, ApiTypes, Config)
- Move internal components to spore/internal/ (Globals)
- Update all #include statements to use new namespace paths
- Update platformio.ini build filters for all environments
- Update all example files to use new include paths
- Maintain backward compatibility for public API
- Improve code organization, maintainability, and scalability

This reorganization follows modern C++ project structure patterns and provides
clear separation between public API, internal implementation, and utilities.
All examples compile successfully with the new structure.

examples/neopixel/NeoPixelService.cpp

@@ -1,5 +1,5 @@
 #include "NeoPixelService.h"
-#include "ApiServer.h"
+#include "spore/core/ApiServer.h"
 
 // Wheel helper: map 0-255 to RGB rainbow
 static uint32_t colorWheel(Adafruit_NeoPixel& strip, uint8_t pos) {