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/ArduinoJson/extras/tests/Misc/NoArduinoHeader.cpp

@@ -0,0 +1,20 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2022, Benoit BLANCHON
+// MIT License
+
+#define ARDUINO 1
+#define ARDUINOJSON_ENABLE_PROGMEM 0
+#define ARDUINOJSON_ENABLE_ARDUINO_STRING 0
+#define ARDUINOJSON_ENABLE_ARDUINO_STREAM 0
+#define ARDUINOJSON_ENABLE_ARDUINO_PRINT 0
+#include <ArduinoJson.h>
+
+#include <catch.hpp>
+
+TEST_CASE("Arduino.h") {
+#ifdef ARDUINO_H_INCLUDED
+  FAIL("Arduino.h should not be included");
+#else
+  INFO("Arduino.h not included");
+#endif
+}