feat(01-02): wifi_server.h/.cpp — AsyncUDP listener with FreeRTOS queue

- RawPacket struct carries raw bytes, IP, port from AsyncUDP callback
- xQueueSendFromISR in callback (ISR-safe) — zero JSON parsing in callback
- parseTask runs in separate FreeRTOS task, drains rawQueue, parses JSON
- STATUS command handled immediately in parseTask with UDP response to sender
- commandQueue declared extern for animation engine (Plan 03) to consume
- main.cpp: include wifi_server.h, call startUdpServer() after WIFI_PS_NONE

firmware/src/main.cpp

@@ -4,6 +4,7 @@
 #include "config.h"
 #include "led_driver.h"
 #include "credentials.h"
+#include "wifi_server.h"
 
 // ---------------------------------------------------------------------------
 // Color constants for startup indicators
@@ -72,11 +73,14 @@ void setup() {
     esp_wifi_set_ps(WIFI_PS_NONE);
     Serial.println("WIFI_PS_NONE set — RMT coexistence mode active");
 
-    // 6. Print connection info
+    // 6. Start UDP server (must be after WiFi connect and WIFI_PS_NONE)
+    startUdpServer();
+
+    // 7. Print connection info
     Serial.print("WiFi connected: ");
     Serial.println(WiFi.localIP().toString());
 
-    // 7. WiFi connected indicator: dim white
+    // 8. WiFi connected indicator: dim white
     setAllWand(COLOR_WIFI_READY);
     showBothStrips();