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/JsonDeserializer/invalid_input.cpp

@@ -0,0 +1,42 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2022, Benoit BLANCHON
+// MIT License
+
+#define ARDUINOJSON_DECODE_UNICODE 1
+#include <ArduinoJson.h>
+#include <catch.hpp>
+
+TEST_CASE("Invalid JSON input") {
+  const char* testCases[] = {"'\\u'",     "'\\u000g'", "'\\u000'", "'\\u000G'",
+                             "'\\u000/'", "\\x1234",   "6a9",      "1,",
+                             "2]",        "3}"};
+  const size_t testCount = sizeof(testCases) / sizeof(testCases[0]);
+
+  DynamicJsonDocument doc(4096);
+
+  for (size_t i = 0; i < testCount; i++) {
+    const char* input = testCases[i];
+    CAPTURE(input);
+    REQUIRE(deserializeJson(doc, input) == DeserializationError::InvalidInput);
+  }
+}
+
+TEST_CASE("Invalid JSON input that should pass") {
+  const char* testCases[] = {
+      "nulL",
+      "tru3",
+      "fals3",
+      "'\\ud83d'",         // leading surrogate without a trailing surrogate
+      "'\\udda4'",         // trailing surrogate without a leading surrogate
+      "'\\ud83d\\ud83d'",  // two leading surrogates
+  };
+  const size_t testCount = sizeof(testCases) / sizeof(testCases[0]);
+
+  DynamicJsonDocument doc(4096);
+
+  for (size_t i = 0; i < testCount; i++) {
+    const char* input = testCases[i];
+    CAPTURE(input);
+    REQUIRE(deserializeJson(doc, input) == DeserializationError::Ok);
+  }
+}