Add support for 2.1" round GC9B72 display, EC11 rotary encoder, Chronometer mode, and 3D printable console case

[macikm]

Summary of Changes

This PR adds full hardware and software support for building a desktop aviation console using a 2.1" round 360×360 GC9B72 SPI display and an EC11 rotary encoder, complete with a custom 3D-printable enclosure.

Key Features Added:

• Display Engine: Migrated to LovyanGFX for high-performance 40 MHz SPI DMA rendering on the 2.1" round GC9B72 panel.
• Rotary Encoder (EC11):
  • Rotate knob to smoothly switch radar zoom range (5, 10, 15, 25 km) or browse aircraft targets.
  • Push button to cycle between Radar, Aircraft Details, and Aviator Chronometer Clock modes.
  • Virtual VCC/GND driving directly from ESP32-C3 GPIOs.
• Aviator Chronometer Mode: Full-screen aviation-style analog clock with date window, digital time readout, and automatic NTP synchronization.
• Aircraft Detail Screen: Dedicated display of selected flight parameters (altitude, speed vector, distance, bearing, track).
• 3D Printable Desktop Enclosure (cad/):
  • Parametric OpenSCAD source (cad/plane_radar_case.scad) with 18° desk tilt and face-down support-free printing.
  • Ready-to-print STL files for the front console and ventilated backplate.
• Updated Documentation: Complete wiring diagram and pinout table for ESP32-C3 Super Mini + GC9B72 + EC11.

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