dpg-gauges

Dear PyGui gauge widgets for dashboards and telemetry displays.

Current implementation status: Step 3 widget shells are implemented. Gauge creation functions still register pure gauge state without requiring a Dear PyGui context, and when a Dear PyGui context is active they create a group plus drawlist shell with placeholder frame and value text rendering.

Runtime value updates are intended for the Dear PyGui GUI thread. Attached gauges redraw immediately for simple value/configuration changes.