feat(ui-lvgl): e-ink graphics in colour on the L2

Node detail: a card with a compass rose and the hop chain over the info;
the bar keeps Message / Admin / Add, Ping and Navigate, the rest goes to a
"More" group under the info (favourite toggled in place, delete by a second
tap). Nodes: an arrow by each distance. A trail's height profile in Map
tools and a saved trail's popup. Diagnostics > History: battery, noise,
SNR and traffic charts. Clock > Calendar: today, the weekend and alarm days.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

examples/companion_radio/ui-lvgl/UITask.h

@@ -432,6 +432,8 @@ private:
   void buildDiag();
   void diagSection(int sec);
   void refreshDiag();
+  void sampleHistory();            // DiagScreen.h: History's readings, from loop()
+  void fillHistory();
   void buildCompass();
   void refreshCompass();
   void favPickPopup(int slot);