Import ESP_UniClock (upstream 1189810)

Vendored from https://github.com/gpeter62/ESP_UniClock: the sketch
source, the web UI and the libraries the ESP8266 build needs, unpacked
from the bundled zips. Adds a PlatformIO project for the ESP-12. The
source is unchanged; local changes follow as separate commits.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

firmware/uniclock/lib/ESPAsyncTCP/src/async_config.h

@@ -0,0 +1,35 @@
+#pragma once
+
+#ifndef ASYNC_TCP_SSL_ENABLED
+#define ASYNC_TCP_SSL_ENABLED 0
+#endif
+
+#ifndef TCP_MSS
+// May have been definded as a -DTCP_MSS option on the compile line or not.
+// Arduino core 2.3.0 or earlier does not do the -DTCP_MSS option.
+// Later versions may set this option with info from board.txt.
+// However, Core 2.4.0 and up board.txt does not define TCP_MSS for lwIP v1.4
+#define TCP_MSS (1460)
+#endif
+
+// #define ASYNC_TCP_DEBUG(...) ets_printf(__VA_ARGS__)
+#define TCP_SSL_DEBUG(...) ets_printf(__VA_ARGS__)
+// #define ASYNC_TCP_ASSERT( a ) do{ if(!(a)){ets_printf("ASSERT: %s %u \n", __FILE__, __LINE__);}}while(0)
+
+// Starting with Arduino Core 2.4.0 and up the define of DEBUG_ESP_PORT
+// can be handled through the Arduino IDE Board options instead of here.
+// #define DEBUG_ESP_PORT Serial
+
+// #define DEBUG_ESP_ASYNC_TCP 1
+#define DEBUG_ESP_TCP_SSL 0
+#include <DebugPrintMacros.h>
+
+#ifndef ASYNC_TCP_ASSERT
+#define ASYNC_TCP_ASSERT(...) do { (void)0;} while(false)
+#endif
+#ifndef ASYNC_TCP_DEBUG
+#define ASYNC_TCP_DEBUG(...) do { (void)0;} while(false)
+#endif
+#ifndef TCP_SSL_DEBUG
+#define TCP_SSL_DEBUG(...) do { (void)0;} while(false)
+#endif