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/ESPAsyncWiFiManager/library.json

@@ -0,0 +1,13 @@
+{
+  "name": "ESPAsyncWiFiManager",
+  "keywords": "wifi, wi-fi",
+  "description": "ESP8266 Async WiFi Connection manager with fallback web configuration portal",
+  "repository":
+  {
+    "type": "git",
+    "url": "https://github.com/alanswx/ESPAsyncWiFiManager.git"
+  },
+  "frameworks": "arduino",
+  "platforms": ["espressif8266", "espressif32"],
+  "version": "0.22"
+}