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/JsonSerializer/JsonVariant.cpp

@@ -0,0 +1,121 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2022, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson.h>
+#include <catch.hpp>
+#include <limits>
+
+template <typename T>
+void check(T value, const std::string &expected) {
+  DynamicJsonDocument doc(4096);
+  doc.to<JsonVariant>().set(value);
+  char buffer[256] = "";
+  size_t returnValue = serializeJson(doc, buffer, sizeof(buffer));
+  REQUIRE(expected == buffer);
+  REQUIRE(expected.size() == returnValue);
+}
+
+TEST_CASE("serializeJson(JsonVariant)") {
+  SECTION("Undefined") {
+    check(JsonVariant(), "null");
+  }
+
+  SECTION("Null string") {
+    check(static_cast<char *>(0), "null");
+  }
+
+  SECTION("const char*") {
+    check("hello", "\"hello\"");
+  }
+
+  SECTION("string") {
+    check(std::string("hello"), "\"hello\"");
+
+    SECTION("Escape quotation mark") {
+      check(std::string("hello \"world\""), "\"hello \\\"world\\\"\"");
+    }
+
+    SECTION("Escape reverse solidus") {
+      check(std::string("hello\\world"), "\"hello\\\\world\"");
+    }
+
+    SECTION("Don't escape solidus") {
+      check(std::string("fifty/fifty"), "\"fifty/fifty\"");
+    }
+
+    SECTION("Escape backspace") {
+      check(std::string("hello\bworld"), "\"hello\\bworld\"");
+    }
+
+    SECTION("Escape formfeed") {
+      check(std::string("hello\fworld"), "\"hello\\fworld\"");
+    }
+
+    SECTION("Escape linefeed") {
+      check(std::string("hello\nworld"), "\"hello\\nworld\"");
+    }
+
+    SECTION("Escape carriage return") {
+      check(std::string("hello\rworld"), "\"hello\\rworld\"");
+    }
+
+    SECTION("Escape tab") {
+      check(std::string("hello\tworld"), "\"hello\\tworld\"");
+    }
+
+    SECTION("NUL char") {
+      check(std::string("hello\0world", 11), "\"hello\\u0000world\"");
+    }
+  }
+
+  SECTION("SerializedValue<const char*>") {
+    check(serialized("[1,2]"), "[1,2]");
+  }
+
+  SECTION("SerializedValue<std::string>") {
+    check(serialized(std::string("[1,2]")), "[1,2]");
+  }
+
+  SECTION("Double") {
+    check(3.1415927, "3.1415927");
+  }
+
+  SECTION("Zero") {
+    check(0, "0");
+  }
+
+  SECTION("Integer") {
+    check(42, "42");
+  }
+
+  SECTION("NegativeLong") {
+    check(-42, "-42");
+  }
+
+  SECTION("UnsignedLong") {
+    check(4294967295UL, "4294967295");
+  }
+
+  SECTION("True") {
+    check(true, "true");
+  }
+
+  SECTION("OneFalse") {
+    check(false, "false");
+  }
+
+#if ARDUINOJSON_USE_LONG_LONG
+  SECTION("NegativeInt64") {
+    check(-9223372036854775807 - 1, "-9223372036854775808");
+  }
+
+  SECTION("PositiveInt64") {
+    check(9223372036854775807, "9223372036854775807");
+  }
+
+  SECTION("UInt64") {
+    check(18446744073709551615U, "18446744073709551615");
+  }
+#endif
+}