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/PubSubClient/tests/testcases/mqtt_basic.py

@@ -0,0 +1,39 @@
+import unittest
+import settings
+import time
+import mosquitto
+
+
+def on_message(mosq, obj, msg):
+    obj.message_queue.append(msg)
+
+
+class mqtt_basic(unittest.TestCase):
+
+    message_queue = []
+
+    @classmethod
+    def setUpClass(self):
+        self.client = mosquitto.Mosquitto("pubsubclient_ut", clean_session=True, obj=self)
+        self.client.connect(settings.server_ip)
+        self.client.on_message = on_message
+        self.client.subscribe("outTopic", 0)
+
+    @classmethod
+    def tearDownClass(self):
+        self.client.disconnect()
+
+    def test_one(self):
+        i = 30
+        while len(self.message_queue) == 0 and i > 0:
+            self.client.loop()
+            time.sleep(0.5)
+            i -= 1
+        self.assertTrue(i > 0, "message receive timed-out")
+        self.assertEqual(len(self.message_queue), 1, "unexpected number of messages received")
+        msg = self.message_queue[0]
+        self.assertEqual(msg.mid, 0, "message id not 0")
+        self.assertEqual(msg.topic, "outTopic", "message topic incorrect")
+        self.assertEqual(msg.payload, "hello world")
+        self.assertEqual(msg.qos, 0, "message qos not 0")
+        self.assertEqual(msg.retain, False, "message retain flag incorrect")