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/MixedConfiguration/issue1707.cpp

@@ -0,0 +1,17 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2022, Benoit BLANCHON
+// MIT License
+
+#define ARDUINO
+#define memcpy_P(dest, src, n) memcpy((dest), (src), (n))
+
+#include <ArduinoJson.h>
+
+#include <catch.hpp>
+
+TEST_CASE("Issue1707") {
+  StaticJsonDocument<128> doc;
+
+  DeserializationError err = deserializeJson(doc, F("{\"hello\":12}"));
+  REQUIRE(err == DeserializationError::Ok);
+}