feat(route): trace per link, to the node or the last repeater, find where it stops; channel order re-sorts on entry

Core: PathEditor results are links (node k hearing k-1 and back); toNode()
off traces only the repeaters (a companion answers only with repeat on);
probe() traces to each repeater in turn after no reply; failures carry a
reason; an empty list saves "direct". PingEngine takes over a slot left past
its timeout. A kept route: the dropped heard path isn't announced to the app
nor bumps lastmod; an app update keeps the flag only if it leaves the route.
Marker boxes sized for every dot and name (overflow).

ui-lvgl Route: one line per node with out / back dB coloured by quality, tap
a hop to move / remove, tap the node to include it, Keep in the header, Find
where beside a no-reply status. ui-new Path: To node / Find break rows,
result alerts, cursor kept on its action.

Channels: ui-new re-sorts the list on entering it, cursor on the same channel.
Docs: Path and trace, Channel order. Sim hooks: open route, add channel,
open messages.

Checked in the browser sim (L2 + ui-new peer + repeater); not on hardware.

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

examples/companion_radio/ui-new/UITask.cpp

@@ -256,6 +256,10 @@ void UITask::openAdminFor(const ContactInfo& ci, bool from_picker) {
   setCurrScreen(admin_screen);   // runs AdminScreen::onShow()'s reset first
   ((AdminScreen*)admin_screen)->startFor(ci, from_picker);
 }
+void UITask::openRouteFor(const uint8_t* pub_key) {
+  setCurrScreen(nearby_screen);   // its onShow() reset first
+  ((NearbyScreen*)nearby_screen)->openRoute(pub_key);
+}
 void UITask::gotoDashboardConfig() { setCurrScreen(dashboard_config); }
 void UITask::gotoTrailScreen()     { setCurrScreen(trail_screen); }
 void UITask::gotoCompassScreen()   { setCurrScreen(compass_screen); }