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/version.cpp

@@ -0,0 +1,18 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2022, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson/version.hpp>
+#include <catch.hpp>
+#include <sstream>
+
+using Catch::Matchers::StartsWith;
+
+TEST_CASE("ARDUINOJSON_VERSION") {
+  std::stringstream version;
+
+  version << ARDUINOJSON_VERSION_MAJOR << "." << ARDUINOJSON_VERSION_MINOR
+          << "." << ARDUINOJSON_VERSION_REVISION;
+
+  REQUIRE_THAT(ARDUINOJSON_VERSION, StartsWith(version.str()));
+}