M2 step 5: GNSS App, with the Position and Sky views

Position: the Fix line (or how long it has been searching), latitude and
longitude in decimal degrees or degrees-minutes-seconds (Settings ->
Coordinates), the Maidenhead locator, altitude, speed and course, HDOP
and UTC. Sky: the satellites by azimuth and elevation, coloured by
constellation, filled when used in the Fix, with used/in-view counts.
Tab switches. lib/gnss/geo_format holds the formatting, the locator and
the sky projection, host-tested (6 tests; locators checked against
FN31pr and JN58td).

Verified on the device by a window: 3D Fix from GPS, GLONASS, Galileo
and BeiDou.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

src/main.cpp

@@ -8,6 +8,7 @@
 
 #include "app_manager.h"
 #include "apps/demo_app.h"
+#include "apps/gnss_app.h"
 #include "apps/irc_app.h"
 #include "apps/launcher_app.h"
 #include "apps/settings_app.h"
@@ -165,6 +166,7 @@ void setup() {
     launcher.setManager(*apps);
     apps->registerApp({"irc", "IRC", false, new IrcApp(*irc, *clockService, bus)});
     apps->registerApp({"wifi-tools", "Wi-Fi Tools", false, new WifiToolsApp(*wifi, *storageService, *clockService)});
+    apps->registerApp({"gnss", "GNSS", false, new GnssApp(*gnssService, settings)});
     apps->registerApp({"settings", "Settings", false,
                        new SettingsApp({settings, bus, *apps, *battery, *storageService, *clockService, *wifi, *savedNetworks, *update})});
     apps->registerApp({"demo", "Widget demo", true, new DemoApp(bus)});