feat(streaming): introduce WebSocket Streaming API bridging event bus

ApiServer: add AsyncWebSocket at /ws; accept JSON {event, payload} (string or object) and dispatch via ctx.fire; mirror all local events to clients using NodeContext::onAny.\nNodeContext: add onAny subscriber API.\nNeoPatternService: add api/neopattern/color event to set solid color.\nCluster: centralize cluster/broadcast sending in core; services delegate.\nAPI: add generic /api/node/event and /api/cluster/event endpoints in respective services.\nTests: add ws-color-client, ws-cluster-broadcast-color, http-cluster-broadcast-color.\nDocs: add StreamingAPI.md; update README and test/README.\nFixes: robust WS JSON parsing on ESP8266 and payload handling.

include/spore/core/ApiServer.h

@@ -2,6 +2,7 @@
 #include <Arduino.h>
 #include <ArduinoJson.h>
 #include <ESPAsyncWebServer.h>
+#include <AsyncWebSocket.h>
 #include <Updater.h>
 #include <functional>
 #include <vector>
@@ -39,6 +40,7 @@ public:
 
 private:
     AsyncWebServer server;
+    AsyncWebSocket ws{ "/ws" };
     NodeContext& ctx;
     TaskManager& taskManager;
     std::vector<std::reference_wrapper<Service>> services;
@@ -48,4 +50,7 @@ private:
     void registerEndpoint(const String& uri, int method, 
                          const std::vector<ParamSpec>& params,
                          const String& serviceName);
+
+    // WebSocket helpers
+    void setupWebSocket();
 };

include/spore/core/NodeContext.h

@@ -23,7 +23,10 @@ public:
 
     using EventCallback = std::function<void(void*)>;
     std::map<std::string, std::vector<EventCallback>> eventRegistry;
+    using AnyEventCallback = std::function<void(const std::string&, void*)>;
+    std::vector<AnyEventCallback> anyEventSubscribers;
 
     void on(const std::string& event, EventCallback cb);
     void fire(const std::string& event, void* data);
+    void onAny(AnyEventCallback cb);
 };