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/Time/examples/Processing/SyncArduinoClock/readme.txt

@@ -0,0 +1,9 @@
+SyncArduinoClock is a Processing sketch that responds to Arduino requests for 
+time synchronization messages.
+
+The portIndex must be set the Serial port connected to Arduino.
+
+Download TimeSerial.pde onto Arduino and you should see the time 
+message displayed when you run SyncArduinoClock in Processing.
+The Arduino time is set from the time on your computer through the 
+Processing sketch.