Initial implementation

Contains JSON hanshake and heartbeat procedure, including rejecting
handshake when no data exposed by connector
Simple loading screen, and then UI opens, no major UI work has been done
yet

src/dynalab/ui/windows.py

@@ -0,0 +1,29 @@
+# Copyright (C) 2026 Hector van der Aa <hector@h3cx.dev>
+# Copyright (C) 2026 Association Exergie <association.exergie@gmail.com>
+# SPDX-License-Identifier: GPL-3.0-or-later
+import dearpygui.dearpygui as dpg
+
+import dpg_gauges as dpgg
+
+from dynalab.tags import MENU_WINDOW_DATA_INPUT
+
+
+def build_loading() -> None:
+    with dpg.window(label="DynaLab", tag="loading_window", no_collapse=True):
+        dpg.set_global_font_scale(0.5)
+        dpg.add_text(default_value="Loading DynaLab", tag="loading_text")
+
+
+def build_windows() -> None:
+    with dpg.window(label="DynaLab", tag="main_window", no_collapse=True):
+        with dpg.menu_bar():
+            with dpg.menu(label="File"):
+                dpg.add_menu_item(label="Quit", enabled=True)
+            with dpg.menu(label="Window"):
+                dpg.add_menu_item(label="Data Input")
+
+        with dpg.child_window(
+            tag="content_area", autosize_x=True, height=0, border=False
+        ):
+            with dpg.group(tag=MENU_WINDOW_DATA_INPUT):
+                dpgg.status_light(label="JSON", show_value=False)