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/CMakeLists.txt

@@ -0,0 +1,30 @@
+# ArduinoJson - https://arduinojson.org
+# Copyright © 2014-2022, Benoit BLANCHON
+# MIT License
+
+set(CMAKE_CXX_STANDARD 98)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+add_subdirectory(catch)
+
+link_libraries(ArduinoJson catch)
+
+include_directories(Helpers)
+add_subdirectory(Cpp11)
+add_subdirectory(Cpp17)
+add_subdirectory(Cpp20)
+add_subdirectory(FailingBuilds)
+add_subdirectory(IntegrationTests)
+add_subdirectory(JsonArray)
+add_subdirectory(JsonDeserializer)
+add_subdirectory(JsonDocument)
+add_subdirectory(JsonObject)
+add_subdirectory(JsonSerializer)
+add_subdirectory(JsonVariant)
+add_subdirectory(MemoryPool)
+add_subdirectory(Misc)
+add_subdirectory(MixedConfiguration)
+add_subdirectory(MsgPackDeserializer)
+add_subdirectory(MsgPackSerializer)
+add_subdirectory(Numbers)
+add_subdirectory(TextFormatter)