Register /gpu-fan handler in setup() using global server variable

- Add webHandlerRegistered flag to prevent duplicate registration
- Call registerWebHandler() in both setup() and connected()
- Use global 'server' variable directly with lambda
- Removed unused methods

usermods/GPU_Fan_Controller/GPU_Fan_Controller.cpp

@@ -41,6 +41,7 @@ class GPUFanControllerUsermod : public Usermod {
     // Configuration
     bool enabled = true;
     bool initDone = false;
+    bool webHandlerRegistered = false;
     int8_t pwmPin = PWM_FAN_PIN;
     
     #ifdef ARDUINO_ARCH_ESP32
@@ -219,9 +220,16 @@ class GPUFanControllerUsermod : public Usermod {
       }
     }
 
-    // Serve the curve editor page
-    static void serveGpuFanPage(AsyncWebServerRequest *request) {
-      request->send_P(200, "text/html", GPU_FAN_HTML);
+    // Register web handler - call this once
+    void registerWebHandler() {
+      if (webHandlerRegistered) return;
+      
+      server.on("/gpu-fan", HTTP_GET, [](AsyncWebServerRequest *request) {
+        request->send_P(200, "text/html", GPU_FAN_HTML);
+      });
+      
+      webHandlerRegistered = true;
+      DEBUG_PRINTLN(F("GPU Fan: Web handler registered at /gpu-fan"));
     }
 
   public:
@@ -231,11 +239,16 @@ class GPUFanControllerUsermod : public Usermod {
       setFanPWM((fixedSpeedPct * 255) / 100);  // Initial speed
       lastTempUpdate = millis();
       initDone = true;
+      
+      // Register web handler immediately during setup
+      registerWebHandler();
+      
       DEBUG_PRINTLN(F("GPU Fan Controller initialized"));
     }
 
     void connected() override {
-      // Nothing special needed on WiFi connect
+      // Also try to register here in case setup was too early
+      registerWebHandler();
     }
 
     void loop() override {
@@ -265,16 +278,6 @@ class GPUFanControllerUsermod : public Usermod {
       return false;
     }
 
-    // Register the /gpu-fan endpoint
-    void addToJsonState(JsonObject& root) override {
-      // This is called during setup, we can use it to register our endpoint
-    }
-
-    // Called when web server is ready - register our custom page
-    void onStateChange(uint8_t callMode) override {
-      // Not the best place, but works
-    }
-
     // Add info to the WLED info panel
     void addToJsonInfo(JsonObject& root) override {
       JsonObject user = root["u"];
@@ -291,7 +294,7 @@ class GPUFanControllerUsermod : public Usermod {
       uiDomString += F("}});\"><i class=\"icons ");
       uiDomString += enabled ? "on" : "off";
       uiDomString += F("\">&#xe08f;</i></button>");
-      uiDomString += F(" <a href=\"/gpu-fan\" style=\"color:#e94560;font-size:0.9em;\">[Curve Editor]</a>");
+      uiDomString += F(" <a href=\"/gpu-fan\" target=\"_blank\" style=\"color:#e94560;font-size:0.9em;\">[Editor]</a>");
       infoArr.add(uiDomString);
 
       if (enabled) {
@@ -450,11 +453,6 @@ class GPUFanControllerUsermod : public Usermod {
       return !top["curve-t1"].isNull();
     }
 
-    // Register web handler
-    void addToWebHandlers(AsyncWebServer& server) {
-      server.on("/gpu-fan", HTTP_GET, serveGpuFanPage);
-    }
-
     uint16_t getId() override {
       return USERMOD_ID_UNSPECIFIED;  // Change this if you add to const.h
     }