Keep T-Deck radio2 scanning active during screen redraws

Render into a PSRAM canvas and release the shared SPI bus between bounded TFT strips. Service only the radio driver at cooperative checkpoints and use the buffered radio HAL, preserving packet and transmit guards.

Cover pixel parity, transaction boundaries, allocation failure, partial updates and sleep/wake behavior with native tests.

.github/workflows/run-unit-tests.yml

@@ -969,6 +969,7 @@ jobs:
           python3 -B test/test_wireless_tracker_display_detection.py -v
           python3 -B test/test_heltec_r8_display_detection.py -v
           python3 -B test/test_heltec_r8_display_rotation.py -v
+          python3 -B test/test_tdeck_display_cooperation.py -v
           python3 -B test/test_muzi_accessory_detection.py -v
           python3 -B test/test_techo_lite_display_detection.py -v
           python3 -B test/test_companion_headless_buttons.py -v