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/MemoryPool/StringCopier.cpp

@@ -0,0 +1,93 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2022, Benoit BLANCHON
+// MIT License
+
+#include <ArduinoJson/StringStorage/StringCopier.hpp>
+#include <catch.hpp>
+
+using namespace ARDUINOJSON_NAMESPACE;
+
+TEST_CASE("StringCopier") {
+  char buffer[4096];
+
+  SECTION("Works when buffer is big enough") {
+    MemoryPool pool(buffer, addPadding(JSON_STRING_SIZE(5)));
+    StringCopier str(pool);
+
+    str.startString();
+    str.append("hello");
+
+    REQUIRE(str.isValid() == true);
+    REQUIRE(str.str() == "hello");
+    REQUIRE(pool.overflowed() == false);
+  }
+
+  SECTION("Returns null when too small") {
+    MemoryPool pool(buffer, sizeof(void*));
+    StringCopier str(pool);
+
+    str.startString();
+    str.append("hello world!");
+
+    REQUIRE(str.isValid() == false);
+    REQUIRE(pool.overflowed() == true);
+  }
+
+  SECTION("Increases size of memory pool") {
+    MemoryPool pool(buffer, addPadding(JSON_STRING_SIZE(6)));
+    StringCopier str(pool);
+
+    str.startString();
+    str.save();
+
+    REQUIRE(1 == pool.size());
+    REQUIRE(pool.overflowed() == false);
+  }
+
+  SECTION("Works when memory pool is 0 bytes") {
+    MemoryPool pool(buffer, 0);
+    StringCopier str(pool);
+
+    str.startString();
+    REQUIRE(str.isValid() == false);
+    REQUIRE(pool.overflowed() == true);
+  }
+}
+
+static const char* addStringToPool(MemoryPool& pool, const char* s) {
+  StringCopier str(pool);
+  str.startString();
+  str.append(s);
+  return str.save().c_str();
+}
+
+TEST_CASE("StringCopier::save() deduplicates strings") {
+  char buffer[4096];
+  MemoryPool pool(buffer, 4096);
+
+  SECTION("Basic") {
+    const char* s1 = addStringToPool(pool, "hello");
+    const char* s2 = addStringToPool(pool, "world");
+    const char* s3 = addStringToPool(pool, "hello");
+
+    REQUIRE(s1 == s3);
+    REQUIRE(s2 != s3);
+    REQUIRE(pool.size() == 12);
+  }
+
+  SECTION("Requires terminator") {
+    const char* s1 = addStringToPool(pool, "hello world");
+    const char* s2 = addStringToPool(pool, "hello");
+
+    REQUIRE(s2 != s1);
+    REQUIRE(pool.size() == 12 + 6);
+  }
+
+  SECTION("Don't overrun") {
+    const char* s1 = addStringToPool(pool, "hello world");
+    const char* s2 = addStringToPool(pool, "wor");
+
+    REQUIRE(s2 != s1);
+    REQUIRE(pool.size() == 12 + 4);
+  }
+}