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/JsonArray/iterator.cpp

@@ -0,0 +1,52 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2022, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+template <typename TArray>
+static void run_iterator_test() {
+  StaticJsonDocument<JSON_ARRAY_SIZE(2)> doc;
+  JsonArray tmp = doc.to<JsonArray>();
+  tmp.add(12);
+  tmp.add(34);
+
+  TArray array = tmp;
+  typename TArray::iterator it = array.begin();
+  typename TArray::iterator end = array.end();
+
+  REQUIRE(end != it);
+  REQUIRE(12 == it->template as<int>());
+  REQUIRE(12 == static_cast<int>(*it));
+  ++it;
+  REQUIRE(end != it);
+  REQUIRE(34 == it->template as<int>());
+  REQUIRE(34 == static_cast<int>(*it));
+  ++it;
+  REQUIRE(end == it);
+}
+
+TEST_CASE("JsonArray::begin()/end()") {
+  SECTION("Non null JsonArray") {
+    run_iterator_test<JsonArray>();
+  }
+
+  SECTION("Null JsonArray") {
+    JsonArray array;
+
+    REQUIRE(array.begin() == array.end());
+  }
+}
+
+TEST_CASE("JsonArrayConst::begin()/end()") {
+  SECTION("Non null JsonArrayConst") {
+    run_iterator_test<JsonArrayConst>();
+  }
+
+  SECTION("Null JsonArrayConst") {
+    JsonArrayConst array;
+
+    REQUIRE(array.begin() == array.end());
+  }
+}