Add flight route lookup, helicopter marker, and QR code for WebUI

Detail panel now shows origin/destination via adsbdb.com callsign
lookup. Rotorcraft (ADS-B category A7) get a distinct rotor-cross
marker instead of a heading arrowhead, same rationale as the existing
ground-vehicle marker. WebUI info screen gets a QR button (when WiFi
is connected) that renders the local WebUI URL as a scannable code.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

platformio.ini

@@ -18,6 +18,7 @@ lib_deps =
     https://github.com/PaulStoffregen/XPT2046_Touchscreen.git
     bblanchon/ArduinoJson @ ^7.0.4
     mikalhart/TinyGPSPlus @ ^1.1.0
+    ricmoo/QRCode @ ^0.0.1
 
 build_flags =
     -D USER_SETUP_LOADED=1