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/JsonDocument/createNested.cpp

@@ -0,0 +1,66 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2022, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+TEST_CASE("JsonDocument::createNestedArray()") {
+  DynamicJsonDocument doc(4096);
+
+  SECTION("promotes to array") {
+    doc.createNestedArray();
+
+    REQUIRE(doc.is<JsonArray>());
+  }
+}
+
+TEST_CASE("JsonDocument::createNestedArray(key)") {
+  DynamicJsonDocument doc(4096);
+
+  SECTION("key is const char*") {
+    SECTION("promotes to object") {
+      doc.createNestedArray("hello");
+
+      REQUIRE(doc.is<JsonObject>());
+    }
+  }
+
+  SECTION("key is std::string") {
+    SECTION("promotes to object") {
+      doc.createNestedArray(std::string("hello"));
+
+      REQUIRE(doc.is<JsonObject>());
+    }
+  }
+}
+
+TEST_CASE("JsonDocument::createNestedObject()") {
+  DynamicJsonDocument doc(4096);
+
+  SECTION("promotes to array") {
+    doc.createNestedObject();
+
+    REQUIRE(doc.is<JsonArray>());
+  }
+}
+
+TEST_CASE("JsonDocument::createNestedObject(key)") {
+  DynamicJsonDocument doc(4096);
+
+  SECTION("key is const char*") {
+    SECTION("promotes to object") {
+      doc.createNestedObject("hello");
+
+      REQUIRE(doc.is<JsonObject>());
+    }
+  }
+
+  SECTION("key is std::string") {
+    SECTION("promotes to object") {
+      doc.createNestedObject(std::string("hello"));
+
+      REQUIRE(doc.is<JsonObject>());
+    }
+  }
+}